Dell 2707WFP: Looking for the Middle Ground of Large LCDs
by Jarred Walton on April 4, 2007 10:00 AM EST- Posted in
- Displays
Response Times and Buffering
A topic that almost always comes up as a problem with LCDs is their slower response times relative to CRTs. There's no doubt that even the best LCDs still exhibit some slight pixel smearing, but the vast majority of users are okay with the level of performance we have available now. Image retention on your retinas also occurs to some extent, so even if you can completely eliminate the smearing effect at the display level you won't necessarily "see" a perfectly crisp transition.
Besides lag at the pixel level, there's also potential for buffering lag within the LCD's image processor before anything is ever sent to the panel for output. This can be particularly noticeable on some HDTVs when connected to a computer, as HDTVs will often do a significant amount of image processing. Whether or not delays are caused by the internal circuitry or by the LCD crystal matrix taking a moment to align itself isn't really important; the end result is what matters, so a display that updates quicker is usually preferred, especially by gamers.
Like the Dell 2407WFP and Gateway FPD2485W LCDs (which also sport S-PVA panels), the 2707WFP advertises 16ms TrTf and 6ms GTG response times. Other LCDs are rated even faster, and ratings aren't always accurate, so let's see how these displays compare in practical use. We use the Dell 2407WFP as our baseline model for all lag/smearing tests; it actually is regarded as being a slightly slower display due to buffering within the panel circuitry, but so far we haven't been able to find any LCDs that are more than one frame faster.
The Dell 2407WFP is on the left in all of the following images. We then started the first game demo from 3DMark03 and took numerous pictures, after which we selected several representing the best and worst case results that we could find. With all of the LCDs running a 60 Hz refresh rate, new frames are sent to the display every 0.017 seconds, so that's our granularity. Pay attention to the value of the Time field in the following screenshots, as that will show whether the two displays are showing the same frame or not. Results for the other displays are available at the following links:
Acer AL2216W #1 Acer AL2216W #2
Dell 2405FPW #1 Dell 2405FPW #2
Dell 3007WFP #1 Dell 3007WFP #2
Gateway FPD2485W #1
HP LP3065 #1 HP LP3065 #2
Despite having the same rated response times, the 2707WFP always seems to be the same or slightly behind the 2407WFP on the actual content being shown. There doesn't appear to be any more pixel lag, but the signal processing lag may be adding almost 1 frame to the transition times. Then again, you can clearly see the artifacts from image tearing, particularly in the first image, and you can see that our refresh locations are not identical, so that may account for the differences at the bottom of the display were the time and frame number are located. Too bad we don't have higher refresh rates available on LCD panels (yet).
In practice, we couldn't tell that either display was any faster/better in terms of image smearing. It was only when we resorted to using a camera that we could capture the slight differences between the displays. It's entirely possible that those with more acute eyesight might be able to notice a difference, but we feel that most people won't have a problem with the slight image smearing that occurs on modern LCDs. As we've said in the past, this is something that will vary by individual, so if you are bothered by image smearing be sure try out a display in person to see if it's suitable for your needs.
A topic that almost always comes up as a problem with LCDs is their slower response times relative to CRTs. There's no doubt that even the best LCDs still exhibit some slight pixel smearing, but the vast majority of users are okay with the level of performance we have available now. Image retention on your retinas also occurs to some extent, so even if you can completely eliminate the smearing effect at the display level you won't necessarily "see" a perfectly crisp transition.
Besides lag at the pixel level, there's also potential for buffering lag within the LCD's image processor before anything is ever sent to the panel for output. This can be particularly noticeable on some HDTVs when connected to a computer, as HDTVs will often do a significant amount of image processing. Whether or not delays are caused by the internal circuitry or by the LCD crystal matrix taking a moment to align itself isn't really important; the end result is what matters, so a display that updates quicker is usually preferred, especially by gamers.
Like the Dell 2407WFP and Gateway FPD2485W LCDs (which also sport S-PVA panels), the 2707WFP advertises 16ms TrTf and 6ms GTG response times. Other LCDs are rated even faster, and ratings aren't always accurate, so let's see how these displays compare in practical use. We use the Dell 2407WFP as our baseline model for all lag/smearing tests; it actually is regarded as being a slightly slower display due to buffering within the panel circuitry, but so far we haven't been able to find any LCDs that are more than one frame faster.
The Dell 2407WFP is on the left in all of the following images. We then started the first game demo from 3DMark03 and took numerous pictures, after which we selected several representing the best and worst case results that we could find. With all of the LCDs running a 60 Hz refresh rate, new frames are sent to the display every 0.017 seconds, so that's our granularity. Pay attention to the value of the Time field in the following screenshots, as that will show whether the two displays are showing the same frame or not. Results for the other displays are available at the following links:
Acer AL2216W #1 Acer AL2216W #2
Dell 2405FPW #1 Dell 2405FPW #2
Dell 3007WFP #1 Dell 3007WFP #2
Gateway FPD2485W #1
HP LP3065 #1 HP LP3065 #2
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| Click to enlarge |
Despite having the same rated response times, the 2707WFP always seems to be the same or slightly behind the 2407WFP on the actual content being shown. There doesn't appear to be any more pixel lag, but the signal processing lag may be adding almost 1 frame to the transition times. Then again, you can clearly see the artifacts from image tearing, particularly in the first image, and you can see that our refresh locations are not identical, so that may account for the differences at the bottom of the display were the time and frame number are located. Too bad we don't have higher refresh rates available on LCD panels (yet).
In practice, we couldn't tell that either display was any faster/better in terms of image smearing. It was only when we resorted to using a camera that we could capture the slight differences between the displays. It's entirely possible that those with more acute eyesight might be able to notice a difference, but we feel that most people won't have a problem with the slight image smearing that occurs on modern LCDs. As we've said in the past, this is something that will vary by individual, so if you are bothered by image smearing be sure try out a display in person to see if it's suitable for your needs.
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AnnonymousCoward - Friday, April 6, 2007 - link
Slightly off topic, but what's the easiest way to get color profiles to apply in games, and not just Windows?JarredWalton - Friday, April 6, 2007 - link
If you set a color profile, it applies to everything but overlay. So games automatically use it, AFAIK. It's only video content that has problems.AnnonymousCoward - Friday, April 6, 2007 - link
You're probably right, since I tried changing the color profile to make everything hot pink, and the game also looked that way.Whenever Windows is booting up, the desktop first looks slightly lighter, and after a second it seems like the color profile kicks in. When I run the game Dark Messiah, right before the screen switches to the game, the desktop switches back to that lighter appearance, so it doesn't look like it's using the profile. I've also seen a few sites indicate that profiles don't apply for games: http://www.hex2bit.com/products/product_mcw.asp">http://www.hex2bit.com/products/product_mcw.asp says "...to prevent other programs from changing the color profile Windows uses. This is especially important to gamers as most games will change the color profile Windows uses." and http://www.hardforum.com/showthread.php?t=1064124&...">http://www.hardforum.com/showthread.php?t=1064124&... someone said "Also, that color profile won't effect videos, games, or your mouse cursor. I calibrated through my spyder2..."
sm8000 - Wednesday, April 4, 2007 - link
"single-link with a very limiting 1280x800 resolution"Isn't single link's max res 1920x1200? I'm pretty sure it is. Is the article saying dual link panels by design won't display more than 1280x800 on single link?
JarredWalton - Wednesday, April 4, 2007 - link
Right. There are no scaler ICs for 2560x1600 right now, but apparently they can manage a simple doubling of resolution. If you use a 30" LCD with a single-link DVI connection, they will only support up to 1280x800. In the case of the HP LP3065, any other resolution ends up being garbled (i.e. the BIOS, POST, and boot sequence is illegible). Within Windows, you can change the resolution and apparently the GPU will handle the scaling, but outside of Windows you're basically out of luck unless you're running 1280x800.jc44 - Wednesday, April 4, 2007 - link
I feel the need to take issue with the assumption in the article that a denser pixel pitches must lead to smaller text. OK - that certianly happens by default, but it is possible to increase the number of dpi that windows associates with amonitor and that should increase the size of the displayed text. I'll admit that support is somewhat patchy with web pages being amongst the greatest offenders - but in general it works.Personally I'm a dpi junkie and normally use a 204dpi monitor which can lead to somewhat interesting results on applications & web pages that are convinced that all monitors in the world run at 96dpi!
These days you don't need to spend a lot on a graphics card to a a dual-link dvi connector - I'm not sure where the bottom of the range is but an nvidia 7600 costs less than £100 and can be found with one dual + one single link DVI connectors.
JC
JarredWalton - Wednesday, April 4, 2007 - link
Adjusting DPI is certainly possible, and I believe this is one of the areas that Vista is supposed to be a lot better than XP. (Anyone able to confirm that?) However, my personal experience with modifying the DPI has been less than stellar. I usually end up just increasing the font size in Firefox, using the magnification in Word, etc. There are plenty of other applications that have no respect for the Windows DPI setting.nullpointerus - Wednesday, April 4, 2007 - link
Vista is definitely better than XP in this regard, but there are still many areas that could use some polish. For example, Vista still appears to use tiny bitmapped icons, which do not scale very well on the high-dpi title bar and task bar. Moreover, many third-party applications and even many Microsoft applications still have icons and images that scale horribly without the standard 96-dpi setting.Nonetheless, font-handling and layout for non-Aero-native applications has improved dramatically since the early Vista RC1 release; instead of merely upscaling the fonts and controls into a blurry mess, the layout engine does proper spacing and the font engine draws crisp, high resolution fonts. Visual Studio 2005 shows *major* progress in this regard.
For anyone interested in getting a higher density display and using the Vista DPI setting, I definitely trying it first. You could enable 120 dpi on your old monitor and stand back an extra foot or so to mimic the effect of a lower pixel pitch. Or get a friend to do this if you do not have Vista on your own computer.
strikeback03 - Wednesday, April 4, 2007 - link
I always reduce the size of my windows icons anyway. they are huge in the stock setting.on a related note, anyone know how to change desktop icon size and spacing in Gnome/Ubuntu? do you need a whole new theme? icons for mounted drives are way large.
nullpointerus - Wednesday, April 4, 2007 - link
typo: I definitely recommend trying it first.