3D Vision Blog

A normal user's look into the world of 3D Stereo Technologies

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Input lag on Samsung 2233RZ and ViewSonic VX2268wm

October 3rd, 2009 · 12 Comments · Other S3D Tech


120hz-samsung-viewsonic


Finally I was able to get a hold of a 120Hz ViewSonic VX2268wm monitor for testing and of course to be able to compare it to the already available Samsung 2233RZ I’ve had for quite some time. Both displays have some differences in design and functionality and although they both use the same LCD TFT panel they do differ in the results they provide. There was one thing that I needed to be certain of, because it might be vital for some gamers playing in 2D mode (especially in FPS games) and even for the people using these displays with 3D Vision to play in stereoscopic 3D mode. You probably guessed already that I’m talking about input lag or the time that the video signal coming out of the video card needs in order to be processed by the electronics of the display, before it can be visualized on the screen. And here we are talking about fractions of a second or milliseconds, but even 1 ms can be vital to winning or to cost you your life in some very fast paced FPS games like Counter Strike or Quake Live for instance. So if a display has absolutely no input lag this means that you get no disadvantage of actually seeing things with some delay and you’ll be able to react faster. And how is the situation with the input lag on Samsung 2233RZ and ViewSonic VX2268wm…


samsung-viewsonic-lcd-input-lag


So on the picture above (shot with a shutter at 1/1000 of a second) you can see that both 120Hz displays are pretty close to each other (display almost the same time on the stopwatch in the game NFS SHIFT), but the ViewSonic is a bit faster. This is actually how the input lag reflects your gameplay… it is just like you see the previous frame on the screen and thus your reaction time gets a few milliseconds added because of that. The biggest difference i was able to observe between the two displays was 10-15 milliseconds, meaning that the Samsung has at least 1 ms input lag if we consider that the ViewSonic has no input lag at all. And considering that the average reaction time for a gamer (pushing a mouse button after seeing something on the screen for instance) is somewhere lets say around 200 milliseconds this is a significant delay as usually a normal person (meaning not a gamer), but with good reflexes can have a reaction time of about 220-235 ms. So basically what the presence of input lag means is that it can take away the advantage you may have in some FPS game over some not so good people just because they have less input lag or none at all.


viewsonic-vs-crt-input-lag


In general it is considered that a good CRT display is capable of having no input lag at all and that is why people do compare for the presence of input lag in an LCD display by testing it next to a CRT monitor. So let me show you something interesting comparing the ViewSonic LCD to Samsung NF900 CRT monitor which was actually quite good monitor back in its time when we used mostly CRTs, they are pretty much the same in terms of input lag. The Viewsonic should not have any or lets say that is should be with less than 1 millisecond input lag, which is much better if you only play fast paced FPS games, but won’t make much difference if you are an RPG fan for instance. Anyway, these tests can be considered just preliminary as they are done in clone mode, the next step is to compare with a DVI splitter cable from a single output port of the video card to confirm or not these results, so stay tuned for more. Also if anyone has both VX2268wm and VX2265wm displays from ViewSonic and can compare them it will be great, because it is possible that the two displays provide completely different results from each other.

As for any possible issues regarding the input lag and 3D Vision, normally there should be no problems because the input lag is not that big to create some visual problem when displaying the images on screen at 120Hz or is it? In order to get 120 frames per second you need to have the each frame displayed on the screen for just about 8 milliseconds and this means that we have almost two whole frames delayed when displaying. But still this is one frame for an eye as in 3D mode we actually see 60 frames per eye and this should not be that much of a problem, or then again is it? I mean this could actually be a cause for getting more visible ghosting for instance on the Samsung than on the ViewSonic displays, because the shutters on the glasses need to be very precisely synced to the images on the screen and this does not include any input lag the monitor can have. Anyway, this is something more like a thing to think about as I need to do a little bit more testing in order to be sure, but on the subjective side I do think I notice a bit less ghosting on the Viewsonic than on the Samsung display, but then again this is completely subjective…

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