Trying to get Motocross Madness 2 running at full graphics settings at 1024x768.

Here are the system specs:
PII 350
512MB RAM
TNT2 Ultra 32MB
DirectX 8
Nvidia driver version 23.11

With that config, I was getting around 15fps, so the first thing I thought to try was to swap the CPU with a PIII 550 I have. That helped some, got the FPS above 20 and was overall smoother. But wanting to see if it was CPU or video card bound, I swapped out the TNT2 with a Geforce3. Since doing that the game never loads, most of the time freezing on a the level load screen or occasionally at the Microsoft logo. I have tried several different versions of the drivers. Changing the resolution doesn't seem to change the frame rate much (2-4fps at most), so I am thinking the bottleneck is the CPU. Putting back in the TNT2 Ultra, with the PIII 550 and I get right at 20fps and it is playable, however it still does sportily freeze the system.

Playing older DOS games is just as important, so I am prepared to keeping the older hardware in and just lowering the resolution if I have to. But this got me wondering if performance was dependent more on CPU than the video card.

Is the Geforce 3 really going to offer a performance improvement if I can get the game to run?