According to my own experience, there is a noticable dependency on memory speed aswell as CPU power.
On my old accelerator, I could change the memory speed.
Using 60ns RAM was clearly faster than using 80ns (I think it was). I also tried disabling the accelerator's RAM and used RAM in the PCMCIA-slow. This was slower than running with chipmem only! :-)
I managed to get 30ish FPS when using a 40 MHz 030, 60ns RAM, and medium details. Made the game a joy to play.
Needless to say, the game runs at ancredible speeds under UAE. :-D