This is pure deception. True DMA uses a hardware bus master, like a PCI or AGP graphics accelerator. Game developers and users should prefer AGP s DMA mode because it offers excellent performance while still being architecturally compatible with the installed base of PCI accelerators. As we all know, Intel is always trying to stir up more ways to persuade users to dump their PCI Pentium 233 systems ASAP, and go buy a more costly P2 AGP system. This way, the graphics card can begin fetching the texture before it is needed to paint pixels on the screen.
Concurrency is one of the keys to performance.
In AGP Execute mode, texture accesses are driven by the rasterizer at the final stage of the 3D pipeline. At this point, the accelerator is dead if it cannot have immediate access to textures. In this way, AGP creates a nasty performance bottleneck. Copyright of all documents and scripts belonging to this site by Thomas Pabst 1996 - 2001. Most of the information contained on this site is copyrighted material.