Actually speaking of Beneath A Steel Sky, that's a game style that often will take advantage of a faster cpu. I remember playing Monkey Island on a stock a500 after being used to it on an a1200 with fast ram and the difference is quite noticable. Another game I noticed speeds up with a faster cpu is the original Street Fighter 2 port by US Gold. It's not any smoother unfortunately though, just faster.
Faster CPU does not fill the gaps of lack of animation frames
It just can make the animation to be played faster.