IN ORDER TO IMPROVE the performance of the integrated X700 graphics on the RS690T chipset, we can reveal that ATI have decided to add the option of a local frame buffer to their north bridge.
This is mainly to get around a major limitation of the K8 platform: lower memory latency to the CPU comes at the expense of higher memory latency to the integrated GPU on the north bridge. Instead of talking to the RAM directly, as on an Intel GMCH, AMD chipsets must look over the HT bus to the memory controller on the CPU, which can badly decrease performance of integrated graphics. Which aren"t exactly the best performing devices in the world anyway.