In the BIOS setup screen on my P4P800 Deluxe there is an item called Graphic Aperture Size. The description is "Allows you to set the size of mapped memory for AGP graphic data." The default setting is 64 MB. I'm running a Radeon 9500 Pro with 128 MB. Does this mean I should change the Graphic Aperture Size in BIOS to 128 MB?
It's the amount of RAM AGP is allowed to use for caching textures. A lot has been writen about this in the past, with wacky formulas for figuring out the amount to use and everything. My best performance has been with it set at 128MB, regardless of everything else.
<font color=blue>Watts mean squat if you don't have quality!</font color=blue>
see, try changing it to 64 but not increase. This is just a chunk of the system memory which is shared by video card if video memory is not enough to handle graphics. If the video card has enough memory it doesn't even need to use this part of the memory. In your case, 128 on the video card is usually enough to handle all the graphic needs and so there is no need to access system memory.