From what I've heard some physics is based on your framerate. That means you'll be able to jump higher for instance if your framerate is higher. Also there is a tangible smoothness increase every 30fps you go up (till you're over 200 or so, I imagine.)
The smoothness stops increasing once you reach double your monitor's refresh rate, in my theory. At least, I haven't noticed. Say your refresh rate is 80hz(CRT). Based on this theory, 160FPS is your best maximum(unless you want to 'cheat' with physics bugs). At 60hz, 120FPS is your best maximum(and is also a physics magic number(whoops, I've said too much)).
stop bitching I get 30fps in GPP and 90 in 1.1 (with a Pent. 4)
Wow. I have a Pent. 4 and I get about 200. (com_maxfps at 333 of course)
That fps is not because of your processor.
Actually it very much can be, as nearly 90% of ioQuake3's renderer is software. There are very few GL functions called in the code(Carmack commented on the quality of drivers being the main reason back in 1999).