lcd panel input lag in stock

When you"re using a monitor, you want your actions to appear on the screen almost instantly, whether you"re typing, clicking through websites, or gaming. If you have high input lag, you"ll notice a delay from the time you type something on your keyboard or when you move your mouse to when it appears on the screen, and this can make the monitor almost unusable.

For gamers, low input lag is even more important because it can be the difference between winning and losing in games. A monitor"s input lag isn"t the only factor in the total amount of input lag because there"s also delay caused by your keyboard/mouse, PC, and internet connection. However, having a monitor with low input lag is one of the first steps in ensuring you get a responsive gaming experience.

Any monitor adds at least a few milliseconds of input lag, but most of the time, it"s small enough that you won"t notice it at all. There are some cases where the input lag increases so much to the point where it becomes noticeable, but that"s very rare and may not necessarily only be caused by the monitor. Your peripherals, like keyboards and mice, add more latency than the monitor, so if you notice any delay, it"s likely because of those and not your screen.

There"s no definitive amount of input lag when people will start noticing it because everyone is different. A good estimate of around 30 ms is when it starts to become noticeable, but even a delay of 20 ms can be problematic for reaction-based games. You can try this tool that adds lag to simulate the difference between high and low input lag. You can use it to estimate how much input lag bothers you, but keep in mind this tool is relative and adds lag to the latency you already have.

There are three main reasons why there"s input lag during computer use, and it isn"t just the monitor that has input lag. There"s the acquisition of the image, the processing, and finally actually displaying it.

The acquisition of the image has to do with the source and not with the monitor. The more time it takes for the monitor to receive the source image, the more input lag there"ll be. This has never really been an issue with PCs since previous analog signals were virtually instant, and current digital interfaces like DisplayPort and HDMI have next to no inherent latency. However, some devices like wireless mice or keyboards may add delay. Bluetooth connections especially add latency, so if you want the lowest latency possible in the video acquisition phase, you should use a wired mouse or keyboard or get something wireless with very low latency.

The time this step takes is affected by the speed of the video processor and the total amount of processing. Although you can"t control the processor speed, you can control how many operations it needs to do by enabling and disabling settings. Most picture settings won"t affect the input lag, and monitors rarely have any image processing, which is why the input lag on monitors tends to be lower than on TVs. One of these settings that could add delay is variable refresh rate, but most modern monitors are good enough that the lag doesn"t increase much.

Once the monitor has processed the image, it"s ready to be displayed on the screen. This is the step where the video processor sends the image to the screen. The screen can"t change its state instantly, and there"s a slight delay from when the image is done processing to when it appears on screen. Our input lag measurements consider when the image first appears on the screen and not the time it takes for the image to fully appear (which has to do with our Response Time measurements). Overall, the time it takes to display the image has a big impact on the total input lag.

Now, let"s talk about how we measure the input lag. It"s a rather simple test because everything is done by our dedicated photodiode tooland special software. We use this same tool for our response time tests, but it measures something differently with those. For the input lag, we place the photodiode tool at the center of the screen because that"s where it records the data in the middle of the refresh rate cycle, so it skews the results to the beginning or end of the cycle. We connect our test PC to the tool and the TV. The tool flashes a white square on the screen and records the amount of time it takes until the screen starts to change the white square; this is an input lag measurement. It stops the measurement the moment the pixels start to change color, so we don"t account for the response time during our testing. It records multiple data points, and our software records an average of all the measurements, not considering any outliers.

When a TV displays a new image, it progressively displays it on the screen from top to bottom, so the image first appears at the top. As we have the photodiode tool placed in the middle, it records the image when it"s halfway through its refresh rate cycle. On a 120Hz TV, it displays 120 images every second, so every image takes 8.33 ms to be displayed on the screen. Since we have the tool in the middle of the screen, we"re measuring it halfway through the cycle, so it takes 4.17 ms to get there; this is the minimum input lag we can measure on a 120Hz TV. If we measure an input lag of 5.17 ms, then in reality it"s only taking an extra millisecond of lag to appear of the screen. For a 60Hz TV, the minimum is 8.33 ms.

Some people may confuse our response time and our input lag tests. For input lag, we measure the time it takes from when the photodiode tool sends the signal to when it appears on-screen. We use flashing white squares, and the tool stops the measurement the moment the screen changes color so that it doesn"t include the response time measurement. As for the response time test, we use grayscale slides, and this test is to measure the time it takes to make a full transition from one gray shade to the next. In simple words, the input lag test stops when the color on the screen changes, and the response time starts when the colors change.

This test measures the input lag of 1080p signals with a 60Hz refresh rate. This is especially important for older console games (like the PS4 or Xbox One) or PC gamers who play with a lower resolution at 60Hz. As with other tests, this is done in Game Mode, and unless otherwise stated, our tests are done in SDR.

This result is important if you play 1440p games, like from an Xbox or a PC. However, 1440p games are still considered niche, and not all TVs support this resolution, so we can"t measure the 1440p input lag of those.

The 4k @ 60Hz input lag is probably the most important result for most console gamers. Along with 1080p @ 60Hz input lag, it carries the most weight in the final scoring since most gamers are playing at this resolution. We expect this input lag to be lower than the 4k @ 60Hz with HDR, chroma 4:4:4, or motion interpolation results because it requires the least amount of image processing.

With the PC sending a 4k @ 60Hz signal, we use an HDFury Linker to add an HDR signal. This is important if you play HDR games, and while it may add some extra lag, it"s still low for most TVs.

The average input lag when all the TV settings are optimized to reduce it at this specific resolution with proper full 4:4:4 chroma, without subsampling.

This test is important for people wanting to use the TV as a PC monitor. Chroma 4:4:4 is a video signal format that doesn"t use any image compression, which is necessary if you want proper text clarity. We want to know how much delay is added, but for nearly all of our TVs, it doesn"t add any delay at all compared to the 4k @ 60Hz input lag.

Like with 1080p @ 60Hz Outside Game Mode, we measure the input lag outside of Game Mode in 4k. Since most TVs have a native 4k resolution, this number is more important than the 1080p lag while you"re scrolling through the menus.

Motion interpolation is an image processing technique that increases the frame rate to a higher one, like if you want to increase a 30 fps video up to 60 fps. However, for most TVs, you need to disable the Game Mode to enable the motion interpolation setting, as only Samsung offers motion interpolation in Game Mode. As such, most TVs will have a high input lag with motion interpolation. Also, we measure this with the motion interpolation settings at their highest because we want to see how the input lag will increase at the strongest, like a worst-case scenario.

We repeat most of the same tests but with 120 fps signals instead. This is especially important for gaming on some gaming consoles, like the Xbox Series X or Xbox One X, as some other devices don"t output signals at 120 fps. The 120Hz input lag should be around half the 60Hz input lag, but it"s not going to be exactly half.

We also measure the input lag with any variable refresh rate (VRR) support enabled, if the TV has it. VRR is a feature gamers use to match the TV"s refresh rate with the frame rate of the game, even if the frame rate drops. Enabling VRR could potentially add lag, so that"s why we measure it, but most TVs don"t have any issue with this. We measure this test by setting the TV to its maximum refresh rate and enabling one of its VRR formats, like FreeSync or G-SYNC.

Input lag is not an official spec advertised by most TV companies because it depends on two varying factors: the type of source and the settings of the television. The easiest way you can measure it is by connecting a computer to the TV and displaying the same timer on both screens. Then, if you take a picture of both screens, the time difference will be your input lag. This is, however, an approximation, because your computer does not necessarily output both signals at the same time. In this example image, an input lag of 40 ms (1:06:260 – 1:06:220) is indicated. However, our tests are a lot more accurate than that because of our tool.

Most people will only notice delays when the TV is out of Game Mode, but some gamers might be more sensitive to input lag even in Game Mode. Keep in mind that the input lag of the TV isn"t the absolute lag of your entire setup; there"s still your PC/console and your keyboard/controller. Every device adds a bit of delay, and the TV is just one piece in a line of electronics that we use while gaming. If you want to know how much lag you"re sensitive to, check out this input lag simulator. You can simulate what it"s like to add a certain amount of lag, but keep in mind this tool is relative to your current setup"s lag, so even if you set it to 0 ms, there"s still the default delay.

The most important setting to ensure you get the lowest input lag possible is the Game Mode setting. This varies between brands; some have Game Mode as its own setting that you can enable within any picture mode, while others have a Game picture mode. Go through the settings on your TV to see which it is. You"ll know you have the right setting when the screen goes black for a second because that"s the TV putting itself into Game Mode.

Some peripherals like Bluetooth mice or keyboards add lag because Bluetooth connections have inherent lag, but those are rarely used with TVs anyways.

Input lag is the time it takes a TV to display an image on the screen from when it first receives the signals. It"s important to have low input lag for gaming, and while high input lag may be noticeable if you"re scrolling through Netflix or other apps, it"s not as important for that use. We test for input lag using a special tool, and we measure the input lag at different resolutions, refresh rates, and with different settings enabled to see how changing the signal type can affect the input lag.

Input lag is the amount of time it takes for a display to process a button input while gaming. If you value your gaming experience, you want to avoid displays that exhibit high input lag, as it makes your gameplay feel sluggish and unresponsive. Our input lag database below will help you avoid laggy displays, as it is the world’s largest database for input lag data.

Stick to displays marked Excellent for the best user experience, as they provide the lowest input lag when set to Game Mode. All displays are tested at 60hz. Most displays of the same model number share nearly identical input lag across size ranges.

It"s false argument to begin with and while I"m glad the Op is fighting back. We need to get out of the mindset a display has input lag, to me it doesn"t it"s literally only displaying the signal given to it and since it has no awareness of your inputs I see it as a dumb notion to link the two.

An ungodly crt like gdm-fw900 has no competition stock or tweaked even compared to oled at 1080p. The same for princeton monitors when the few of them existed for customers and not just big companies or very pricy clients could be gotten. I say that from experience and I"ve yet to see any flat panel in my history post crts or sed demonstrations that have topped either.

how about if we have topic like this we inform people a little more of options in the past that LCD and flat panels made us regress in, such as high refreshrates. That"s huge caveat to leave out to people that CRTs had no problem with high refreshrates even in the 90s. Not only that refreshrate as we now know from the blur buster studies has a direct impact on the pixel persistence of lcd, thus even for lcds it would seem dumb to me not mention that that factor would change at higher rates. I don"t even need to debate this part that"s a fact and it should be highlighted that 60hz alone in pixel persistence is 16MS. There"s no doubt that in high refreshrate test or ulmb test LCD would have even less input lag, which would only help the argument they aren"t as weak as crts in this area. I know this cause I use said such products and immediately see the difference vs shit 60hz.

A high level of input lag can greatly impact your overall gaming experience and especially in twitch-sensitive games. We’d consider anything under 20ms as good for gaming. Options, as high as 68ms, may completely cripple your overall gaming experience. Monitors with high refresh rates that are made for gaming typically fall into this category as the time for each frame to remain on the screen is greatly diminished.  However, there are many cheap gaming monitors available with extremely low latency.

Modern TVs and monitors are often plagued more than previous generation CRT versions as additional processing power and memory storage is is necessary in order to display a command. So most of what is determined as display lag is built-in to your device. However, if you’ve already purchased your TV or monitor, there are some ways to decrease its overall input lag.

Testing for input lag has a lot of processes involved with it. The most rudimentary method we’ve seen of doing this involves recording your display and input at the same time and then trying to calculate the difference in time. There are other better ways of doing this including devices made specifically for this type of testing. These include the Video Signal Input Lag Tester from Leo Bodnar Electronics. Perhaps a more practical way of doing this is to simply go to a site where display lag is measured. Prad.de is one such site but there are many others as well.

Many people get input lag confused with response time. Response time is the time it takes for a pixel to go from black to white and then back again. Often manufacturers will post their GTG or gray to gray response time in order to achieve a lower number. Monitors that have a below 5ms response time typically leave blur with images that move quickly.

Ever wondered whether G-Sync or FreeSync is better or want to know more about them? Linus over at Linus Tech Tips gives us a good comparison to look at. We found this test valuable albeit somewhat unscientific. Different panels will give different results. So, proper testing would involve using a display that is both G-Sync and FreeSync compatible.

Ultimately picking a monitor or HDTV that already comes with a low amount of display lag is the easiest way to make sure you have a smooth gaming experience. If you’ve already bought your monitor or display, try taking some of the steps we mentioned above to remedy the situation.

One of the areas where the A-MVA panel does extremely well is in the areas of display lag and pixel response time. Just to recap, you may have heard complaints about "input lag" on various LCDs, so that"s one area we look at in our LCD reviews. We put input lag in quotation marks because while many people call it "input lag", the reality is that this lag occurs somewhere within the LCD panel circuitry, or perhaps even at the level of the liquid crystals. Where this lag occurs isn"t the concern; instead, we just want to measure the duration of the lag. That"s why we prefer to call it "processing lag" or "display lag".

To test for display lag, we run the Wings of Fury benchmark in 3DMark03, with the output set to the native LCD resolution - in this case 1920x1200. Our test system is a quad-core Q6600 running a Radeon HD 3870 on a Gigabyte GA-X38-DQ6 motherboard - we had to disable CrossFire support in order to output the content to both displays. We connect the test LCD and a reference LCD to two outputs from the Radeon 3870 and set the monitors to run in clone mode.

The reference Monitor is an HP LP3065, which we have found to be one of the best LCDs we currently possess in terms of not having display lag. (The lack of a built-in scaler probably has something to do with this.) While we know some of you would like us to compare performance to a CRT, that"s not something we have around our offices anymore. Instead, we are looking at relative performance, and it"s possible that the HP LP3065 has 20ms of lag compared to a good CRT - or maybe not. Either way, the relative lag is constant, so even if a CRT is faster at updating, we can at least see if an LCD is equal to or better than our reference display.

While the benchmark is looping, we snap a bunch of pictures of the two LCDs sitting side-by-side (using a relatively fast shutter speed). 3DMark03 shows the runtime with a resolution of 10ms at the bottom of the display, and we can use this to estimate whether a particular LCD has more or less processing lag than our reference LCD. We sort through the images and discard any where the times shown on the LCDs are not clearly legible, until we are left with 10 images for each test LCD. We record the difference in time relative to the HP LP3065 and average the 10 results to come up with an estimated processing lag value, with lower numbers being better. Negative numbers indicate a display is faster than the HP LP3065, while positive numbers mean the HP is faster and has less lag.

It"s important to note that this is merely an estimate - whatever the reference monitor happens to be, there are some inherent limitations. For one, LCDs only refresh their display 60 times per second, so we cannot specifically measure anything less than approximately 17ms with 100% accuracy. Second, the two LCDs can have mismatched vertical synchronizations, so it"s entirely possible to end up with a one frame difference on the time readout because of this. That"s why we average the results of 10 images, and we are confident that our test procedure can at least show when there is a consistent lag/internal processing delay. Here is a summary of our results for the displays we have tested so far.

As you can see, all of the S-PVA panels we have tested to date show a significant amount of input lag, ranging from 20ms up to 40ms. In contrast, the TN and S-IPS panels show little to no processing lag (relative to the HP LP3065). The BenQ FP241VW performs similarly to the TN and IPS panels, with an average display lag of 2ms - not something you would actually notice compared to other LCDs. Obviously, if you"re concerned with display lag at all, you"ll want to avoid S-PVA panels for the time being. That"s unfortunate, considering S-PVA panels perform very well in other areas.

Despite what the manufacturers might advertise as their average pixel response time, we found most of the LCDs are basically equal in this area - they all show roughly a one frame "lag", which equates to a response time of around 16ms. In our experience, processing lag is far more of a concern than pixel response times. Taking a closer look at just the FP241VW, we can see the typical one frame lag in terms of pixel response time. However, the panel does appear to be a little faster in response time than some of the other panels we"ve tested (notice how the "ghost image" isn"t as visible as on the HP LP3065), and we didn"t see parts of three frames in any of the test images.

After the initial article went live, one of our readers who works in the display industry sent me an email. He provides some interesting information about the causes of image lag. Below is an (edited) excerpt from his email. (He wished to remain anonymous.)

PVA and MVA have inherent drawbacks with respect to LCD response time, especially gray-to-gray. To address this shortcoming, companies have invested in ASICs that perform a trick generically referred to as "overshoot." The liquid crystal (LC) material in *VA responds sluggishly to small voltage changes (a change from one gray level to another). To fix this, the ASIC does some image processing and basically applies an overvoltage to the electrodes of the affected pixel to spur the LC material into rapid movement. Eventually the correct settling voltage is applied to hold the pixel at the required level matching the input drive level.

It"s very complicated math taking place in the ASIC in real time. It works well but with an important caveat: it requires a frame buffer. What this means is that as video comes into the panel, there is a memory device that can capture one whole video frame and hold it. After comparing it to the next incoming frame, the required overshoot calculations are made. Only then is the first captured frame released to the panel"s timing controller, which is when the frame is rendered to the screen. As you may have already guessed, that causes at least one frame time worth of lag (17ms).

Some companies discovered some unintended artifacts in their overshoot calculations and the only way they saw to correct these was to allow for their algorithm to look ahead by two frames instead of one. So they had to up the memory of the frame buffer and now they started capturing and holding not one but two frames upon which they make their complex overshoot predictions to apply the corrected pixel drive levels and reduce gray-to-gray response time (at the expense of lag time). Again, it works very well for improving response time, but at the expense of causing lag, which gamers hate. That in a nutshell is the basis of around 33ms of the lag measured with S-PVA.

Not every display uses this approach, but this could account for the increase in display lag between earlier S-PVA and later S-PVA panels. It"s also important to note that I tested the Dell 2408WFP revision A00, and apparently revision A01 does not have as much lag. I have not been able to confirm this personally, however. The above also suggest that displays designed to provide a higher image quality through various signal processing techniques could end up with more display lag caused by the microchip and microcode, which makes sense. Now all we need are better algorithms and technologies in order to reduce the need for all of this extra image processing -- or as we have seen with some displays (particularly HDTVs), the ability to disable the image processing.

Display lag is a phenomenon associated with most types of liquid crystal displays (LCDs) like smartphones and computers and nearly all types of high-definition televisions (HDTVs). It refers to latency, or lag between when the signal is sent to the display and when the display starts to show that signal. This lag time has been measured as high as 68 ms,Hz display. Display lag is not to be confused with pixel response time, which is the amount of time it takes for a pixel to change from one brightness value to another. Currently the majority of manufacturers quote the pixel response time, but neglect to report display lag.

For older analog cathode ray tube (CRT) technology, display lag is nearly zero, due to the nature of the technology, which does not have the ability to store image data before display. The picture signal is minimally processed internally, simply for demodulation from a radio-frequency (RF) carrier wave (for televisions), and then splitting into separate signals for the red, green, and blue electron guns, and for the timing of the vertical and horizontal sync. Image adjustments typically involve reshaping the signal waveform but without storage, so the image is written to the screen as fast as it is received, with only nanoseconds of delay for the signal to traverse the wiring inside the device from input to the screen.

For modern digital signals, significant computer processing power and memory storage is needed to prepare an input signal for display. For either over-the-air or cable TV, the same analog demodulation techniques are used, but after that, then the signal is converted to digital data, which must be decompressed using the MPEG codec, and rendered into an image bitmap stored in a frame buffer.

While the pixel response time of the display is usually listed in the monitor"s specifications, no manufacturers advertise the display lag of their displays, likely because the trend has been to increase display lag as manufacturers find more ways to process input at the display level before it is shown. Possible culprits are the processing overhead of HDCP, Digital Rights Management (DRM), and also DSP techniques employed to reduce the effects of ghosting – and the cause may vary depending on the model of display. Investigations have been performed by several technology-related websites, some of which are listed at the bottom of this article.

LCD, plasma, and DLP displays, unlike CRTs, have a native resolution. That is, they have a fixed grid of pixels on the screen that show the image sharpest when running at the native resolution (so nothing has to be scaled full-size which blurs the image). In order to display non-native resolutions, such displays must use video scalers, which are built into most modern monitors. As an example, a display that has a native resolution of 1600x1200 being provided a signal of 640x480 must scale width and height by 2.5x to display the image provided by the computer on the native pixels. In order to do this, while producing as few artifacts as possible, advanced signal processing is required, which can be a source of introduced latency. Interlaced video signals such as 480i and 1080i require a deinterlacing step that adds lag. Anecdotallyprogressive scanning mode. External devices have also been shown to reduce overall latency by providing faster image-space resizing algorithms than those present in the LCD screen.

Many LCDs also use a technology called "overdrive" which buffers several frames ahead and processes the image to reduce blurring and streaks left by ghosting. The effect is that everything is displayed on the screen several frames after it was transmitted by the video source.

Display lag can be measured using a test device such as the Video Signal Input Lag Tester. Despite its name, the device cannot independently measure input lag. It can only measure input lag and response time together.

Lacking a measurement device, measurement can be performed using a test display (the display being measured), a control display (usually a CRT) that would ideally have negligible display lag, a computer capable of mirroring an output to the two displays, stopwatch software, and a high-speed camera pointed at the two displays running the stopwatch program. The lag time is measured by taking a photograph of the displays running the stopwatch software, then subtracting the two times on the displays in the photograph. This method only measures the difference in display lag between two displays and cannot determine the absolute display lag of a single display. CRTs are preferable to use as a control display because their display lag is typically negligible. However, video mirroring does not guarantee that the same image will be sent to each display at the same point in time.

In the past it was seen as common knowledge that the results of this test were exact as they seemed to be easily reproducible, even when the displays were plugged into different ports and different cards, which suggested that the effect is attributable to the display and not the computer system. An in depth analysis that has been released on the German website Prad.de revealed that these assumptions have been wrong. Averaging measurements as described above lead to comparable results because they include the same amount of systematic errors. As seen on different monitor reviews the so determined values for the display lag for the very same monitor model differ by margins up to 16 ms or even more.

Several approaches to measure display lag have been restarted in slightly changed ways but still reintroduced old problems, that have already been solved by the former mentioned SMTT. One such method involves connecting a laptop to an HDTV through a composite connection and run a timecode that shows on the laptop"s screen and the HDTV simultaneously and recording both screens with a separate video recorder. When the video of both screens is paused, the difference in time shown on both displays have been interpreted as an estimation for the display lag.16 ms or even more.

Display lag contributes to the overall latency in the interface chain of the user"s inputs (mouse, keyboard, etc.) to the graphics card to the monitor. Depending on the monitor, display lag times between 10-68 ms have been measured. However, the effects of the delay on the user depend on each user"s own sensitivity to it.

Display lag is most noticeable in games (especially older video-game consoles), with different games affecting the perception of delay. For instance, in PvE, a slight input delay is not as critical compared to PvP, or to other games favoring quick reflexes like

If the game"s controller produces additional feedback (rumble, the Wii Remote"s speaker, etc.), then the display lag will cause this feedback to not accurately match up with the visuals on-screen, possibly causing extra disorientation (e.g. feeling the controller rumble a split second before a crash into a wall).

TV viewers can be affected as well. If a home theater receiver with external speakers is used, then the display lag causes the audio to be heard earlier than the picture is seen. "Early" audio is more jarring than "late" audio. Many home-theater receivers have a manual audio-delay adjustment which can be set to compensate for display latency.

Many televisions, scalers and other consumer-display devices now offer what is often called a "game mode" in which the extensive preprocessing responsible for additional lag is specifically sacrificed to decrease, but not eliminate, latency. While typically intended for videogame consoles, this feature is also useful for other interactive applications. Similar options have long been available on home audio hardware and modems for the same reason. Connection through VGA cable or component should eliminate perceivable input lag on many TVs even if they already have a game mode. Advanced post-processing is non existent on analog connection and the signal traverses without delay.

A television may have a picture mode that reduces display lag for computers. Some Samsung and LG televisions automatically reduce lag for a specific input port if the user renames the port to "PC".

LCD screens with a high response-time value often do not give satisfactory experience when viewing fast-moving images (they often leave streaks or blur; called ghosting). But an LCD screen with both high response time and significant display lag is unsuitable for playing fast-paced computer games or performing fast high-accuracy operations on the screen, due to the mouse cursor lagging behind.

One of the areas where the A-MVA panel does extremely well is in the areas of display lag and pixel response time. Just to recap, you may have heard complaints about "input lag" on various LCDs, so that"s one area we look at in our LCD reviews. We put input lag in quotation marks because while many people call it "input lag", the reality is that this lag occurs somewhere within the LCD panel circuitry, or perhaps even at the level of the liquid crystals. Where this lag occurs isn"t the concern; instead, we just want to measure the duration of the lag. That"s why we prefer to call it "processing lag" or "display lag".

To test for display lag, we run the Wings of Fury benchmark in 3DMark03, with the output set to the native LCD resolution - in this case 1920x1200. Our test system is a quad-core Q6600 running a Radeon HD 3870 on a Gigabyte GA-X38-DQ6 motherboard - we had to disable CrossFire support in order to output the content to both displays. We connect the test LCD and a reference LCD to two outputs from the Radeon 3870 and set the monitors to run in clone mode.

The reference Monitor is an HP LP3065, which we have found to be one of the best LCDs we currently possess in terms of not having display lag. (The lack of a built-in scaler probably has something to do with this.) While we know some of you would like us to compare performance to a CRT, that"s not something we have around our offices anymore. Instead, we are looking at relative performance, and it"s possible that the HP LP3065 has 20ms of lag compared to a good CRT - or maybe not. Either way, the relative lag is constant, so even if a CRT is faster at updating, we can at least see if an LCD is equal to or better than our reference display.

While the benchmark is looping, we snap a bunch of pictures of the two LCDs sitting side-by-side (using a relatively fast shutter speed). 3DMark03 shows the runtime with a resolution of 10ms at the bottom of the display, and we can use this to estimate whether a particular LCD has more or less processing lag than our reference LCD. We sort through the images and discard any where the times shown on the LCDs are not clearly legible, until we are left with 10 images for each test LCD. We record the difference in time relative to the HP LP3065 and average the 10 results to come up with an estimated processing lag value, with lower numbers being better. Negative numbers indicate a display is faster than the HP LP3065, while positive numbers mean the HP is faster and has less lag.

It"s important to note that this is merely an estimate - whatever the reference monitor happens to be, there are some inherent limitations. For one, LCDs only refresh their display 60 times per second, so we cannot specifically measure anything less than approximately 17ms with 100% accuracy. Second, the two LCDs can have mismatched vertical synchronizations, so it"s entirely possible to end up with a one frame difference on the time readout because of this. That"s why we average the results of 10 images, and we are confident that our test procedure can at least show when there is a consistent lag/internal processing delay. Here is a summary of our results for the displays we have tested so far.

As you can see, all of the S-PVA panels we have tested to date show a significant amount of input lag, ranging from 20ms up to 40ms. In contrast, the TN and S-IPS panels show little to no processing lag (relative to the HP LP3065). The BenQ FP241VW performs similarly to the TN and IPS panels, with an average display lag of 2ms - not something you would actually notice compared to other LCDs. Obviously, if you"re concerned with display lag at all, you"ll want to avoid S-PVA panels for the time being. That"s unfortunate, considering S-PVA panels perform very well in other areas.

Despite what the manufacturers might advertise as their average pixel response time, we found most of the LCDs are basically equal in this area - they all show roughly a one frame "lag", which equates to a response time of around 16ms. In our experience, processing lag is far more of a concern than pixel response times. Taking a closer look at just the FP241VW, we can see the typical one frame lag in terms of pixel response time. However, the panel does appear to be a little faster in response time than some of the other panels we"ve tested (notice how the "ghost image" isn"t as visible as on the HP LP3065), and we didn"t see parts of three frames in any of the test images.

After the initial article went live, one of our readers who works in the display industry sent me an email. He provides some interesting information about the causes of image lag. Below is an (edited) excerpt from his email. (He wished to remain anonymous.)

PVA and MVA have inherent drawbacks with respect to LCD response time, especially gray-to-gray. To address this shortcoming, companies have invested in ASICs that perform a trick generically referred to as "overshoot." The liquid crystal (LC) material in *VA responds sluggishly to small voltage changes (a change from one gray level to another). To fix this, the ASIC does some image processing and basically applies an overvoltage to the electrodes of the affected pixel to spur the LC material into rapid movement. Eventually the correct settling voltage is applied to hold the pixel at the required level matching the input drive level.

It"s very complicated math taking place in the ASIC in real time. It works well but with an important caveat: it requires a frame buffer. What this means is that as video comes into the panel, there is a memory device that can capture one whole video frame and hold it. After comparing it to the next incoming frame, the required overshoot calculations are made. Only then is the first captured frame released to the panel"s timing controller, which is when the frame is rendered to the screen. As you may have already guessed, that causes at least one frame time worth of lag (17ms).

Some companies discovered some unintended artifacts in their overshoot calculations and the only way they saw to correct these was to allow for their algorithm to look ahead by two frames instead of one. So they had to up the memory of the frame buffer and now they started capturing and holding not one but two frames upon which they make their complex overshoot predictions to apply the corrected pixel drive levels and reduce gray-to-gray response time (at the expense of lag time). Again, it works very well for improving response time, but at the expense of causing lag, which gamers hate. That in a nutshell is the basis of around 33ms of the lag measured with S-PVA.

Not every display uses this approach, but this could account for the increase in display lag between earlier S-PVA and later S-PVA panels. It"s also important to note that I tested the Dell 2408WFP revision A00, and apparently revision A01 does not have as much lag. I have not been able to confirm this personally, however. The above also suggest that displays designed to provide a higher image quality through various signal processing techniques could end up with more display lag caused by the microchip and microcode, which makes sense. Now all we need are better algorithms and technologies in order to reduce the need for all of this extra image processing -- or as we have seen with some displays (particularly HDTVs), the ability to disable the image processing.

Your monitor’s display settings may increase the delay between inputting commands and seeing the result on your display. Some display parameters are configurable, while others are built into the hardware and cannot be changed.

The first thing to look at is your monitor’s refresh rate. A higher refresh rate increases the number of individual frames that your monitor displays per second. Displaying more frames per second reduces the delay between inputting a command and seeing its result on the screen, shaving valuable milliseconds off input lag.

Not all wired connections provide the same response time benefits. Some displays (especially Smart TVs) add processing effects like visual noise reduction to AV input, which adds to latency. To avoid this, check to see if your TV features a “Game Mode” that minimizes input lag by bypassing video signal processing.

Keep in mind that every TV and monitor has a unique, hardware-defined input latency. This is the amount of time that it takes the display to receive, process, and show incoming data. It is built into the hardware of the screen itself and cannot be changed.

Manufacturers don’t generally advertise their products’ latency delays. Instead, they focus on “response time,” which measures how long it takes for individual pixels to change color. It’s easy to confuse these two, but response time doesn’t have a significant impact on input lag.

Many new, gaming-ready displays have an input latency of 10-15 milliseconds. There are third-party websites that conduct and list monitor input latency scores, so it’s possible to verify how much of your input lag is built in.

If you’re looking to get a new gaming monitor, whether 60Hz, 144Hz, 165hz or even 240Hz, then you’re most likely considering two very important specs. We don’t mean resolution as that’s a given and the first item on the list right next to screen size. We’re referring to input lag and response time. While most prospective gaming monitor shoppers know what refresh (or frame) rate means, quite a few people remain confused about the distinction between response time and input lag.

Additionally, while almost every gaming monitor has a response time listed in the spec section, input lag rarely makes an appearance. That’s because while the confusion exists, the two terms are very different. Manufacturers can easily calculate and test monitor response times at the factory, but input lag (or input latency) presents a much more complex issue. Many factors that go into input lag have nothing to do with the monitor or the production process used to make the display, and so manufacturers would be remiss if they made bold input lag claims.

Despite that, as someone interested in gaming and gaming monitors you should definitely educate yourself on these two related but distinct terms. That’s because if you opt for a cheap monitor that ends up having slow response or lots of lag then your gaming may well be ruined. Even monitors with high refresh rates can be slow in this regard. If they suffer from sluggish response time and high latency your games will present with problems like motion blur and ghosting. Additionally, controlling in-game actions will feel “off” and unresponsive. That’s why gamers really should learn more about response time and input lag plus how the two differ.

Quite a simple answer to that one. Response time forms a part of overall input latency. That most likely explains why so many people misunderstand that the two specs describe different but connected aspects of a gaming monitor. Another cause for confusion may originate in the fact that both refer to speed and have become part of the popular discussion around gaming monitors as things to consider for optimal monitor performance. Often mentioned in the same sentence, response time and input latency sometimes become conflated with each other.

Sure, both tell us important things about a gaming monitor’s speed, but from very different angles. Response time is entirely native to the monitor proper, while input lag or latency include the whole process from you pressing a button to a corresponding action occurring onscreen.

Distilled to their bare essence, both terms detail the speed with which images change on a display and react to your input. But that’s a very simplistic description that doesn’t do the topic justice, so let’s look at them up close.

Response describes the length of time a given monitor or panel needs to change the properties of each pixel. Since TFT LCDs consist of millions of pixels (or transistors), for example 8.3 million in a 4K monitor, speed is understandably of the essence. Response time tells us how long a monitor needs to turn a pixel from red to green, as an example. The faster, the more responsive the image updates. Faster means smoother display and allows for higher refresh rates.

Think of response time like this. You’re playing a first person game and decide to turn left, down an alley. Your monitor gets the data from your PC or console and needs to update the image you see to reflect the new graphics being loaded in. A monitor with 5ms technically does this five times slower than a 1ms screen. Of course, we’re talking about milliseconds so the difference may not be perceptible. But every little bit counts as games by nature need to be responsive, and like we said response time contributes to overall lag or delay.

Different gaming monitor panel types support slightly diverse response times, although advancing technology has helped narrow down gaps. The fastest response occurs on TN panels, which generally are the best for reflex-based gaming. Essentially all TN panels do 1ms these days, which is why they’re the only ones capable of 240Hz refresh rates, as well. VA and IPS panels usually come in at 2ms-5ms but provide better colors and viewing angles. We’ve discussed panel technologies if you want to know more.

TN panels carry out the least pixel processing of the three main panel types, explaining their high speeds. VA and IPS panels have been designed to ensure better colors, but that requires more processing – meaning delays. As the simplest mainstream panel type, TN manages the fastest response times by getting straight to the pixel, so to speak.

The total time required to show an action on the screen amounts to what is known as input lag. The word input mostly refers to you, the user. You press a key or click a button on a keyboard or controller and then expect a corresponding action on your gaming monitor (or TV). The time needed to show you that action equals input lag.

Input lag rises from a host of factors. From your controller or keyboard the signal moves to your PC or console. If you’re using wireless input devices that movement takes a little longer than with wired versions. Then your PC or console take time to process the data you gave them, then more time to send graphics info via a cable to your display. Generally, HDMI and DisplayPort have the same speed: light speed. So cables aren’t a major issue, but they’re a step. Then every monitor has processing units that accept signals and work to update the screen. Thus, the monitor’s internal circuitry introduces lag. Response time factors into latency as we mentioned above. That means the time a monitor needs to get a signal, process that signal, then change its pixels to depict visuals obviously adds latency.

Any image processing done on your monitor increases latency. Even if base response time is 1ms, should the monitor then add refinements like HDR, dynamic brightness/contrast, edge sharpening, local dimming and so forth – well, latency increases. Remember the basic rule: image processing means lag.

That’s why for gaming we recommend using PC mode or game mode. Those switch off most image processing to keep you close to raw response time on the monitor. How do we measure input lag? Also in milliseconds, but it’s a lot more than response time. Really good monitors like the BenQ EL2870U,  the 4K HDR monitor EW3270U, and 144hz gaming monitor EX2780Q with speakers clock in at 9ms-10ms based on third party reviews, but the average hovers somewhere between 15ms and 22ms for typical gaming monitors and gaming-minded TVs. You should not detect any negative effects with those latency figures, and your games will feel very responsive. It’s only when latency exceeds 40ms or so that people begin to notice sync issues. Anything over 50ms would be basically unplayable. Don’t laugh, lots of cheap monitors and TVs even now deliver performance slower than that, resulting in completely ruined gaming experiences.

When shopping for a gaming monitor do some research, read reviews, and check out the spec sheets. You’ll likely find out about each model’s response time easily enough, but reviews and forum posts will shed more light on input lag. Stay with reputable, established brands. Get monitors that specifically mention gaming, as good manufacturers won’t claim gaming-grade performance for slow monitors, it’s simple as that.

Also simple is the difference between response time and input latency. The former is local to the monitor and helps you understand how fast the panel is on its own. The latter refers to a much more comprehensive and useful number because it includes response time and illustrates the actual gaming experience you’ll have with a monitor or TV.

Input lag (or display lag) is the delay between your GPU sending a frame to your monitor and the monitor actually displaying that frame. This is an essential aspect of gaming, where an input lag of 16ms or less is preferred on a 60Hz display.

Input or display lag is the time (measured in milliseconds) it takes for a TV or monitor to react and display the commands you’ve inputted via a device such as a keyboard, a controller, or a mouse.

However, neither TV nor monitor manufacturers state the input lag in the display specifications, which is why doing detailed research before getting a new display is highly recommended.

When looking for a TV for console gaming, it’s of utmost importance to check whether it has this feature. Although some may be more sensitive to high input lag than others, lower is always better.

If you’re looking for a monitor for gaming, there’s usually nothing to worry about as most high refresh rate gaming monitors have low input lag as well as a quick response time speed.

all 4 of these are the same level of accuracy, and drive your monitor directly. Thus they can measure your monitor"s input lag with high accuracy. BUT they cannot determine if there"s something about your computer/OS or video card that"s adding additional latency. Given that you are reporting smear, however, the lag is probably your monitor"s slow response time.