the dreaded input lag

[twotone8]

I was wondering if any of you ever have trouble with input lag, or the delay between a button press and the response on the screen.

I started researching it after i moved to windows 7 and discovered a noticeable delay in my system.

After much agonizing, I discovered some interesting things about modern systems and input lag..

I used this neat little program to manually test for input lag on different computers/displays/controllers etc, and found lots of important variables that can contribute.

Apparently vsync, while doing a great job of removing screen tearing, will also add on average about 1 frame of delay/input lag. This equates to approx 16ms. It doesn't seem like much, but when playing a fighting game or fps, it can really get annoying. This can be avoided by turning vsync off, either in game or through nvidia/ati settings. Turning vsync off brings the delay to about 3ms, which is not noticeable in the slightest. I found this to be true even when using my wireless game controller on an lcd monitor with various resolutions on numerous machines..

Triple buffering is supposed to help as well, and I've read numerous contrasting testimonies about its behavior. My experience reveals that triple buffering acts differently for most programs it's applied to. It usually succeeds in smoothing things out, but it has only alleviated input lag in one game I've tested so far, that being fallout 3. For most games, it actually adds to the input lag.

If you're running an emulator from a window on a windows 7/vista environment, you can eliminate the input lag by either right clicking on the executable, going to the compatibility tab, and choosing to 'disable desktop composition', or you can set specific 3d rendering settings per program in nvidia control panel (not sure about ati). Disabling desktop composition turns off the 'aero' theme while the program is running, thereby removing vsync.

I find it a shame that for 80% of games I run, having the picture synced is simply out of the question. Having your screen tear is not at all pretty, but it beats a lagy control scheme. Even for old legacy 8-bit systems, reaction time is important.

Now I've shared my thoughts on input lag on several forums, but the reason I bring it up here is I'm considering building an HTPC with GameEx as the primary gaming interface. I will most likely be connecting this machine to the display through an HDMI cable. These connections are most common on the newer LCD displays. I figured this wouldn't be a problem, seeing as LCD TVs are becoming more and more common.

The other my roommate brought home a shiny new 42inch lcd tv from samsung, and lo and behold, the input lag is absolutely terrible.

Using the input lag testor utility, which is by no means perfect seeing as it relies on human reaction time, the tv averaged at about 100ms of input lag on default settings. It was absolutely noticeable to the naked eye, and impossible to game on.

Most LCD tv's have a "game mode", which is used to alleviate this very input delay by switching off various video processing functions from the TV. I've heard this makes gameplay just about perfect for Xbox360/PS3 users, but unfortunately this was not an option if using a PC to TV connection via DVI. I had to send away for an HDMI cable, and connect it to the TV just as I would a game console.

With Game Mode enabled, there was still a highly noticeable 40ms of input lag in all resolutions. This is while vsync is completely disabled on my machine. I used a dual-view setup and it was quite clear that the TV was running behind.

I find this tremendously upsetting. Everywhere I've looked on the internet tells me that all LCD TVs are going to have a slight input lag, no matter what you do. I've browsed through these forums and found several lovingly crafted arcade machines which happen to include a monster of an LCD TV as the display. Has the hardcore gaming community found a solution that is eluding me? Or is it that most folks don't tend to notice or care about reaction time when gaming.

This sort of takes some of the wind out of my sails in terms of building an HTPC for gaming. I don't like the idea that I can spend a modest few hundred dollars, build a portable gaming machine that I'm very proud of, and have no way to connect it to a modern tv without game breaking input lag.

I haven't tested a modern gaming console with the TV, so I can't say whether or not it's any different with them. If the main consoles have indeed found a way to circumvent the input lag of HDTV's, I would hope that this would make it's way to the PC world eventually.

Any tips, advice, or insight?