Dell U2711 Lag and Response Time

Some users are very concerned with display lag and pixel response time. For others, they really don't notice anything unless a particular display is very sluggish. I fall into the latter camp, though I do notice the processing lag when it's above ~40ms (e.g. on the Dell 2408WFP and LaCie 324, my mouse input just felt off.) 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 2560x1440. We clone the output to our reference LCD, an HP LP3065, snap a bunch of pictures, toss out any where the time readout isn't clear, and then average the remaining results (at least 10, and usually 20 or more).

As a reminder, the reference HP LP3065 is 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, few users have CRTs these days and all we're really interested in measuring is the relative lag. It's possible we will find an LCD that ends up with a negative result, meaning it's faster than the LP3065, but the best we have managed so far is a tie.

Processing Lag Comparison

So far, all of the S-PVA panels we have tested show a significant amount of input lag, ranging from 18ms 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 with an S-MVA panel 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. What about the new U2711?

We tested with the "Graphics" setting and Adobe RGB as well as "Video" and "Game" - we figured the latter might disable some post-processing and result in less lag. That turned out to be incorrect, as our measured lag actually went up 2ms. However, in practice the settings are pretty much tied. That means the U2711 has around one frame of lag relative to our best LCDs, but it still has a lot less lag than our worst offenders. As stated already, I didn't notice lag in using the U2711 - just like I didn't notice lag on the 2407WFP or the FPD2485W. I did notice slight lag on the Samsung 245T and some clear lag on the 2408WFP and LaCie 324, but the threshold for lag varies and you'll need to determine if 15-17ms is too much or not for you. If you've tried any TN panels and still noticed lag, we would expect every current LCD to be above your "lag threshold".

Despite what the manufacturers might advertise as their average pixel response time, we have 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. Some transitions are faster than others, but the above is representative of what we found in a study of numerous photos. If you look at the tail of the center plane, you can see a slight ghost image before and after the dominant frame. Some of that will come from the camera (we use a 1/120s shutter speed), but most of it comes from the LCD panel. In this case, the U2711 panel does outperform most LCDs that we've tested, where it was often possible to see at least three frames more clearly than the two slight ghosts in the above image.

Dell U2711 Color Quality Brightness, Contrast, and Power
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  • karielash - Friday, January 22, 2010 - link

    Yes the resolution is worth it, although I went for a 30", the difference between 1080P and 2560x1440 is huge.
  • jigglywiggly - Friday, January 22, 2010 - link

    Haha, you guys are making me feel bad, I have 3xs2409w in a triple monitor setup. They are all tn panels, but they look gorgeous to me. Then again I have had nothing to compare them to.
  • cactusdog - Friday, January 22, 2010 - link

    I hope you guys test Samsungs new cPVA monitors F2370H and F2380MX. It supposedly has a true 3000:1 contrast ratio, TN response times and 100% color gamut.
  • MadMan007 - Friday, January 22, 2010 - link

    How can you knowingly write the title 'New Samsung IPS' then go on to say they are cPVA in the post?? Did you forget the title by the time you wrote the post?
  • cactusdog - Friday, January 22, 2010 - link

    Hahaha, i know. I wrote the title but i thought i better check what kind of monitor it was. I wrote it right in the post cPVA then i forgot to change the title. lol anyway its cPVA
  • MadMan007 - Friday, January 22, 2010 - link

    hehe, sorry, I didn't mean to sound trollish. A review of those monitors would be nice, sure, if just to see how good 'c'PVA is but they aren't really competition for IPS in the professional market because fwir they still have the typical PVA horizontal angle-dependent contrast shift.
  • Zebo - Friday, January 22, 2010 - link

    Correct PVA actually shifts more than TN on horizontal axis (who cares about vertical unless you shift from sitting to standing in front of your desk) PVA is also slowest tech. In sum IPS>TN>VA
  • strikeback03 - Monday, January 25, 2010 - link

    Sorry, having owned and used all three I disagree about putting TN over *VA. And I definitely could see the TN vertical problems just sitting at a desk looking at a 17" 5:4 panel, just the few degree shift in angle from top to bottom caused issues.
  • FlyTexas - Friday, January 22, 2010 - link

    This is a nice panel for those who really need it, however...

    The Dell 3008WFP 30" LCD would be a better choice for most gamers and casual users however, if you're looking to spend this much money.
  • mespejel - Wednesday, February 10, 2010 - link

    you need more information myself, i have the 3008WFP and i'm actually selling this monitor to buy the new U2711.. the technology is simply superior:

    U2711 use H-IPS 3008WFP use S-IPS (H-IPS is much better)
    U2711 use 80000 dynamic contrast ratio.. 3008WFP use 3000
    U2711 have 6ms.. 3008WFP have 8ms

    also the 3008WFP is not really good for movies and you know that (if you own one).. U2711 is amazing for movies

    CNET rate U2711 as much superior as the best 27 inches better.. and they don't rate 3008WFP that high..

    the only advantage of 3008WFP is the size of course, and that is 1600p.. but this monitor is 1440p.. not much difference there!

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