AGP Aperture

The AGP Aperture size is an available option configurable commonly through the computer CMOS (BIOS) setup that is commonly set to a default size of 64MB. AGP aperture size defines how much system memory (not memory on your video card) the AGP controller is allowed to use for texture maps. While it may be possible to increase the overall performance by increasing this value we recommend you leave the AGP aperture size at 64MB unless instructed otherwise by your video card manufacturer. Increasing the size only allocates more system memory and unless the program or game is capable or needs to use it that memory will be left un-used, in addition with some configurations increasing the AGP aperture can cause a decrease in performance.

Also see: AGP, Video definitions