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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  • JarredWalton - Friday, January 22, 2010 - link

    Honestly, I'm sitting in from of my 3007WFP (not the HC version) and moving my head around and I just can't see anything. LOL.

    I'm looking at a white background and I can't see anything bothersome. I just did the same thing with a couple glossy laptops as well as the U2711 and I'm still not seeing anything sparkly. In fact, I just wandered around my lab and looked at six different LCDs (laptop and desktop, glossy and matte) and I'm still at a loss.

    I might actually sort of see what you're referring to, but even then it just doesn't register as something distracting to my brain/eyes. My best guess is that either my eyes just aren't good enough to see it well (entirely possible), or my brain has adapted to where this effect doesn't affect me.

    This is something I try to get across in my display reviews: you know what bothers you and I know what bothers me, and sometimes something that I totally don't see will irritate the hell out of others. If you can see/test a display in person, that's your best bet obviously. I figure if you're spending $1000 on a display, you'll want to do everything you can to make sure it's the right panel for you in advance of laying out the cash.

    Caveat emptor, eh?
    Reply
  • The0ne - Wednesday, January 27, 2010 - link

    Not really. Most of the issues people are referring to and talking about are what I like to call "subjective preferences." People want things the way they like them to be will pay more attention to the features, defects, etc. For most users, they aren't even aware of most of this features/defects to even begin realizing and thus not seeing.

    Selecting a TV is no different. However, once you do start to pay attention to what others are saying then you will begin to notice as it becomes more apparent.

    If you can't see and anomalies on your 30" I wouldn't worry about it or bother to do research. Doing so might just ruin your enjoyment of it. For those that care way way too much, they usually end up here...

    AVS forums :o
    Reply
  • MadMan007 - Friday, January 22, 2010 - link

    You don't need to mvoe your head around to see it. I can get the same sort of thing only less severe on my LP2475W but only if I'm less than one foot away which is not normal use. With Dells I see it very easily from normal distance (2-3 feet.)

    If Dell still has a solid 100% back free shipping return policy on monitors there's little risk in trying them. All I know is when I tried a 2407WFP a few years back even without reference to another LCD I was like 'wtf is this?' and then found comments about the same thing from others. But obviously there are plenty of people who like Dell monitors so it's all personal preference. I was coming from a CRT and it was my first shot at an LCD if that matters but still it was immediately noticable to me. Maybe lighting plays a role too *shrug*

    Given their return policy (if it's still the same) I don't see any problem recommending people try Dell monitors. The strong anti-glare is just something that for people who know they don't like it to the extent it's a deal breaker want to know ahead of time so they just won't bother.
    Reply
  • icrf - Friday, January 22, 2010 - link

    I've got a refurb 3007WFP-HC and it's definitely got the sparkliness going on. I only really noticed it when I first got the display and was scouring for dead pixels (got a couple, but they're hard to see, and the rest is immaculate, so I kept it). I guess I've gotten used to the sparkling, which is a much better term than grainy. It's never bothered me. I strongly prefer it to seeing a reflection of myself like a gloss finish. Reply
  • MadMan007 - Saturday, January 23, 2010 - link

    I guess that's what sucks about being ugly :( ! lol :D Reply
  • dasgib - Friday, January 22, 2010 - link

    Thanks for your answer.

    Just to clarify: large white areas are shown as large, white areas, not as "large dusty/grained kind-of-white-but-not-really-white" areas? ;-)

    Anyway, I'm really looking forward to the release of the devise. I haven't found any 24-inch that has no crappy colours or that frickin' grain :(
    The LP2475w has _incredible_ colours and a very deep black - but it's extremely grainy - even in comparison to a really, really old and really cheap 22-inch TN panel.
    Reply
  • MadMan007 - Friday, January 22, 2010 - link

    If he says it looks the same as the 3007WFP then it likely has the typical Dell anti-glare coating. I just don't think he knows what it looks like or doesn't notice it any more. It just doesn't bother some people. Reply
  • hadphild - Friday, January 22, 2010 - link

    Does this monitor cope with different Hz ranges?

    I am really looking for a monitor that can cope with all hz range up to 60hz. I work in a pro video environment and regularly need to use 50Hz outputs.

    Reply
  • Patrick Wolf - Friday, January 22, 2010 - link

    The only reason I'd see a gamer wanting this is if a resolution that high is really worth sacrificing size since you could just get a much larger (42"?) quality 1080P HDTV for roughly the same price. Reply
  • erple2 - Saturday, January 23, 2010 - link

    If I'm doing work? Yes, I'd much, MUCH rather have more vertical pixels than a larger screen, no comparison at all. I'd pay significantly more for it too, than a "High Quality" TV with crummy resolution.

    I love the 1920x1200 15" screen on my laptop, thank you very much. I love the fact that I can see 4 windows at the same time on it. Using the company provided 14" screen with an (IMO) appalling 1280x800 resolution makes me feel so ... cramped.
    Reply

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