Bez,
The aperture setting depends alot on how much system RAM you have installed in your system.
The Radeon 9700 w. 128 meg video memory is a powerful card, and I wouldn't think you should change your aperture from 64 to 128.
Try benchmarking your system using something like 3D Mark 2001 or something similar. Then try adjusting your aperture setting and running the tests again to find just what setting gives the best results.
Also, keep in mind that by raising the aperature setting, this reserves that amount of RAM for AGP use, and this memory won't be available for games that need it.
Mag...