An AGP inline memory module (AIMM, also known as a GPA or graphics performance accelerator) is a highly specially memory module used only in systems which utilize Intel’s 815E chipset and integrated graphics. AIMM upgrades are used improve a system’s overall video performance. In fact, a 4MB upgrade can improve video performance by approximately 25%. The pins on an AIMM look different than the pins on other modules because an AIMM plugs into an AGP slot (usually used for video cards) instead of the slots used for the main system memory.
The number of black components on a 66-pin AIMM may vary, but they always have exactly 66 pins. (In this photo, the black components are under the label.) 66-pin AIMMs are approximately 3.75″ long and 1.5″ high.