Adding a 4 MB GPA (AIMM) module can usually increase the performance of 3D accelerated applications. The reason for it is that the memory bandwidth to the GPA card can be used simultaneously with the bandwidth to system memory resulting in a larger total bandwidth. 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 so that both can be accessed at the same time. Increased memory bandwidth usually equates to better performance in 3D applications.
Adding system memory can also help with 3D performance, but it does not increase the total memory bandwidth, so the gain may not be as great as adding a GPA card.
This applies to: