14 DAY TRIAL // Some of you may remember that many producers have integrated dedicated onboard memory for their IGPs so one could say that Ati's idea is not that original. But originality is not the issue here, since Ati never claimed it was the first ever to incorporate the idea into a product. Of course applying the idea to a mobile solution is not so simple.
The earlier approaches were however less fortunate. SiS, with their 770 chipset for the K8 platform tried that and even some members of the SiS630, a Pentium III chipset, were blessed with onboard memory just for graphics. I remember that in one situation, it was possible to start the PC and use only the 32MB of integrated GDDR to run the SO (the onboard GDDR was acting as a D-Ram). While such solutions seem appealing at first, the low performance of the integrated GPUs combined with the fact that D-Rams have increased their throughput in the last years render onboard GDDR useless.
X700 graphics on the RS690T chipset will be the first IGP where Ati will use a frame buffer integrated into the northbridge. This idea could help get around a major limitation in the K8 platform design: lower memory latency to the CPU comes at the expense of higher memory latency to the integrated GPU (found on the north bridge). Instead of having direct access to the D-Ram (as INTEL G9xx series does), AMD integrated GPUs access the memory using the HT bus and that translates into a lower performance. It is quite clear that no one would expect an IGP to run Oblivion but an integrated frame buffer could vastly improve the 3D performance.
RS690T's X700 integrated GPU uses the pinout of an X16 PCIE interface and it's said to support up to 128MB of local frame buffer but we don't know if the actual interface will provide the bandwidth of a real x16 interface. On the other hand, being a mobile product means that it won't perform as good as its desktop counterpart anyway. All things considered, I'd like to see a final product based on this idea.