If it gets below 23 FPS you will notice it skipping, but barely.
I consider
5 FPS Hour long load times.
14 FPS not playable
18 FPS Playable
33 FPS to be good,
50 FPS excellent.
60FPS Well I can't tell a difference after 50FPS. ;D
I just like to have 22FPS on my 1mb vid card, thats almost as high as it will go. My brother has an 800mhz with a Voodoo5, sweeeeeet. ;D