To get a noticable improvement in performance, try changing the colour from 32bit to 16bit. It made a big difference to me, and it seems to have almost no affect on the graphics.
Yeah, I have a Radeon 8500 and I geta little improvement in 16bit because my card is optimized for 32 bit. Certain cards gain more performance in 16 bit than others. Folks with GF2's and 3's will get a big boost.