Adding a 4 MB GPA (Graphics Performance Accelerator) card, also known as an AIMM module, can usually increase the performance of 3D accelerated applications with the integrated graphics controller of the Intel® 815/815E chipset. This is true despite the fact that the memory bandwidth for a GPA card is less than that of regular system memory.
The reason for this is that the memory bandwidth to the GPA card can be used simultaneously with the system memory bandwidth, resulting in a larger total bandwidth for video data. For example, the front and back buffers and textures can be stored in system memory, and the Z-buffer can be stored in the GPA card memory. In this setup, both the Z-buffer and back buffer can be accessed at the same time. Increased memory bandwidth usually equals better performance in 3D applications.
Adding system memory can also help with 3D performance, especially if less than 128 MB of system memory is present, but it does not increase the total video memory bandwidth, so the gain may not be as great as adding a GPA card.
This applies to: