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 has also been discussion of late about a buffering lag that occurs within the LCD before the image 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. We glossed over this issue in the previous reviews, but with five LCDs reviewed we can now take a closer look and see if there's any merit to claims of better response times.

The Dell 2407WFP and Gateway FPD2485W LCDs advertise 16ms TrTf and 6ms GTG response times. The older Dell 2405FPW comes with a 12ms TrTf and 16ms GTG response time, which is sort of the opposite of what we see on most current displays. The 3007WFP also lists both types of response times: 14ms TrTf and 11ms GTG. The Acer AL2216W comes with the fastest advertised response time of these displays, boasting a 5ms GTG response time, but it doesn't explicitly state a TrTf value. There are of course other LCDs that are rated even faster, and ratings aren't always accurate, so let's see how these displays compare in practical use.

We used the Dell 2407WFP as the "baseline" display, so it 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 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. The best-case picture is shown on the left and the worst-case is on the right; these are two samples selected out of dozens of images for each pairing of monitors.

Acer AL2216Wbd

Dell 3007WFP

Gateway FPD2485W

Dell 2405FPW

We only chose one image for the FPD2485W, and other than the difference in display brightness, the two screens appear to be virtually identical. Sorting through dozens of pictures, we couldn't find any where the 2407WFP and FPD2485W showed differing content. Those two displays, at least, are a tie when it comes to image response times - including any issues with image buffering. Of the remaining displays, only the 2405FPW is any slower than the 2407WFP, and not by much.

The Acer AL2216W ends up being the best display out of those tested when it comes to image response times - or at least the lack of buffering. The 3007WFP also appears to be slightly faster than the 2407WFP. One thing not immediately visible in the above images, however, is that while the Acer display does not appear to suffer from any image buffering, response times on certain pixel color transitions are slightly worse than the 2407WFP. There were a couple of images where we could see three instances of an object on the AL2216W versus only two images on the 2407WFP.

Having said all that, we never noticed any of this during subjective testing, and it was only when we resorted to using a camera that we could capture the slight differences between the displays. Maybe it's just that we're getting old, but our eyes don't seem to be bothered by a difference of 0.017 seconds. We strongly feel that most people won't have a problem with the slight image smearing that occurs on these LCDs, but this is something that will vary by individual. If you know you are bothered by image smearing, try out a display in person to see if it's suitable for your needs.

Color Gradients Uncalibrated Results
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  • JarredWalton - Monday, March 12, 2007 - link

    Newegg lists a http://www.newegg.com/Product/ProductList.asp?Subm...">bunch of 22" LCDs, with the Acer AL2223Wd and Chimei 221D being the cheapest. Actually, I'm curious as to what the difference in panel is between the AL2216Wbd and the AL2223Wd, as the latter has a better stand IMO. Looks like it has a slightly higher contrast as well - possibly a better display coating? Anyway, you can see in that list that specs are almost all identical between the 22" LCDs, so price and features are going to be the big factors.
  • tercathian - Sunday, March 11, 2007 - link

    w/ Base, (WxHxD)=20.2"x16.0"x7.8"; w/o Base,=27.16"x17.70"2.93". That base must reeaally scrunch things together! Otherwise another great Anandtech review. Glad to see monitors getting coverage again for a change.
    Upon visual comparison of BesBi's display lcd's, I passed on the Acer 22" that had a white line running top to bottom and picked the LG 22". Noticably crisper than any other brand, with purported 3000:1 contrast, for not much more $$$.
  • JarredWalton - Sunday, March 11, 2007 - link

    Oops... yea, wrong display on the w/o stand measurements! I updated the size figures, for those that are interested. I'll also see about getting that LG LCD for review - looks interesting, as they may actually use something other than a TN panel.
  • semo - Sunday, March 11, 2007 - link

    1st, the color gradient for the gateway display links to the dell 2405fpw's (page 6).

    how does the dell 2405fpw look with an average delta e of 10.41? do you look at it and say "hmmm... something's wrong" even if there is no other display to compare it with? just wondering if a home user can detect color inaccuracies and do something about it or you get what you get and hope for the best (i assume a "home user" does not have access calibration equipment).

    for the last several years i've largely ignored anything that has happened in display technology (other than glance over price tags) so imagine my surprise when i decided to bring myself up to date and found the crt is virtually extinct. i bought my pc and tv 5 years ago and crt was everywhere. i always thought i wouldn't switch to the thin stuff for decades and that my next tv would be a cheap hd ready tube.
    anyway, i was wondering when will we see picture quality as good as crt used to provide and is lcd or plasma going to bring it to us. some of the displays at consumer shows seem to deliver the goods but anything that isn't plasma or lcd at the moment is just vaporware.
  • JarredWalton - Sunday, March 11, 2007 - link

    Thanks for the link correction; that's fixed now for the Gateway chart.

    I'm not sure if the colors on the 2405FPW are just getting worse due to age or if it's always been off that far. If it's sitting next to another display display, I can certainly see a difference and the 2405 tends to look a bit washed out/yellow. If it's sitting alone on a desk, it actually doesn't bother me much, and going through some basic color calibration charts (i.e. calibrate by eye without the colorimeter) you can improve the colors to the point where it's about the same as the other displays (around 6-8 average delta E).

    CRTs are dead/dying I think in part because they can't really be any cheaper to produce anymore. Even with current LCD prices, I'd wager the markup on all LCDs continues to be pretty good, while CRTs probably don't get more than a 10-20% markup because the market won't bear it. Especially quality CRTs cost quite a bit more to manufacture, and the companies that used to make such displays (Sony, NEC, etc.) have abandoned the CRT market as far as I'm aware.
  • yyrkoon - Sunday, March 11, 2007 - link

    I still think 22" WS monitors cost too much, you can get a decent 19" WS for $179, so why the $100 markup for 3" diagonal ? It certainly cant be assurance against dead / stuck pixels . . .

    This is another problem I have with paying so much , eTailers, and manufactuers saying "must have 8 dead pixels, or more to replace monitor for a new one". That would be like me saying, "hey man, most of my money is not counterfit, but some of it is, but you can not have your monitor back, becasue you dont have a high enough percentage of bad vs good currency". Would be nice if these 'people' would come around to reality, this is the main reason I personally go through convoltions, every time I plunk down a good bit of my hard earned cash for a LCD . . .

    I've yet to get any dead / stuck pixels, but I figure, it is just a matter of time. Anyhow, would be nice, if 'we the people' could 'rectify' this.
  • JarredWalton - Sunday, March 11, 2007 - link

    The eTailers are just trying to protect themselves, and there's a simple solution: if you can't live with a few dead pixels, shop somewhere else. Local stores usually cost more but have better return policies.

    As for the cost, I paid $1100 for a 2405FPW 18 months back, and $300 for a rather lousy 19" LCD about the same time. Needless to say, while $300 may still be more than some people are willing to pay, prices have become much more reasonable across the board. It wasn't that long ago that 19" LCDs were at the $300+ price point for entry level models, and still people were willing to buy them.
  • yyrkoon - Sunday, March 11, 2007 - link

    I understand WHY eTailers do what they do, but my whole point is basically, why are these companies (OEMs) getting away with what is obviously 'bad business'. I suspect this has to do with some 'fair trade' garbage, something a long the lines of why 3rd world countries are allowed to import food products into countries, that would not normally allow this food in to begin with ( IE, the food does not meet the countries standards for health and wellfare ).

    As for the bad 19" for $300, well, I too also paid ~$300 for one of mine (ViewSonic VA1912wb) around 12-18 months ago, and could not possibly be more pleased with it. Well, ok, maybe if it were free . . . Now, could you imagine, if you just spent $650 on a 24" WS, and had noticable bad pixels ANYWHERE on the screen ? Me, I'd be very upset.

    All I'm really saying, is that 'we' need to let the OEMs this is not acceptable, until then, they will get away with whatever we let them get away with.
  • mindless1 - Monday, March 12, 2007 - link

    It's real simple, they either have to sell the panels with the bad pixels or discard them (throw away if bad enough or divert to lower grade sales which is also a loss).

    If they take back these panels then it will cost more per monitor. They're not "getting away" with anything, if you don't like it don't buy their product. That's the catch, they can stipulate any return policy they like and won't have to alter it if they don't preceive it hurting sales.

    It doesn't really hurt sales much because there aren't that many monitors with that many bad pixels, apparently they already sort the panels well enough that the sort criteria is lower than the defective product return criteria.

    They're only getting away with it if/when someone actually has that many dead pixels. Who do you know that does? Unfortunately a lot of businesses have policies that (if I knew about them), would make be pause before doing business. You end up playing odds, what is your time worth to find a better policy and what other compromises are made with the alternative product? I have one LCD of several that has one stuck pixel. I can accept that as much as I can accept a bug in some other piece of hardware, as most hardware isn't perfect, it's just a matter of whether you notice the flaw or not.
  • yyrkoon - Sunday, March 11, 2007 - link

    All I'm really saying, is that 'we' need to let the OEMs _know_ this is not acceptable, until then, they will get away with whatever we let them get away with.

    Anyhow, IM sorry that my little rant here, kind of hijacked the idea of this discussion area :/ It just seems, that 'the business', is slowly, but surely moving to a 'screw the cutomer for what they're worth' type attitude, and of course, this . . . sucks.

    The good news is: From all the reviews of read on acer monitors over the last few months, have been very favorable on their behalf, at least concerning dead/stuck pixels, other issues do seem to pleague random models however, such as LCD not comming up until windows is booting (need to change BIOS settings ? SoL buddy . . .), to others not working properly with dual monitors attached to a video card ( monitor not operating at 'optimal' resolution).

    Some of these issues would not likely bother the average user, while it would effect those who do need to adjust BIOS settings (without hooking up another monitor), or run dual monitors, etc, etc.

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