Grimbergen is my gaming box

I don't think the GFX card is the limiting factor, changing the res from 800x600 to 1280x960 made no noticeable difference, aside from looking better.
I think it simply requires either tons of CPU, or lots of memory, it runs fine in most situations, but when there's lots of stuff on the screen, it slows down.
Shadows are off by the way.