[citation][nom]alidan[/nom]most games i play are around the 40 fps mark, a few get into the 30 range but even than i dont notice input lag unless there is something seriously wrong with the engine, like witcher 2, for some reason i got that game going at around 40fps, but the mouse is so lagged that its about half a second to second slower than it should be, mean while i got crysis at max just for the hell of it to see what it would look like, even though its choppy, the mouse doesn't feel like its lagged. with the rift and the future of the rift, im not expecting 0 lag at all, just an acceptable amount, which by all accounts could end up being less lag than computer to traditional monitor.[/citation]
The latency on any 1st person or over the shoulder view game caused by low FPS is very apparent to me if I'm using a mouse, and apparent enough I get sick from it. I experience nausea, others get headaches or eye strain. This is known as simulator sickness.
I used to power through it until I learned that higher FPS and better hardware resolved it. At 30-40 FPS, first person games are unbearable. At 50-70 FPS, it isn't too bad, at 80+ FPS, it goes away (I have a 120hz monitor btw).
It is there, and while you may not experience simulator sickness, the US Army once did a study on it, and found that 40%-50% of those who used their simulators got some form of simulator sickness.