AnandTech heard Intel's 975X chipset will likely not support NVIDIA's SLI and it looks like this chipset won't be launched in November but close to the launch of Intel's Napa Centrino platform.
975X will feature two PEG slots in a dual 8 lane configuration, more than ample bandwidth to run two NVIDIA 7800GTX or two ATI X800XT cards in tandem. Originally, we expected the 975X launch date only a few weeks out; manufacturers have working samples they were able to show us in Taiwan this week. Unfortunately for Intel, this launch has been pushed back to January. One product manager mentioned to us that the reason for the delay was actually the immaturity of [ATI and Intel] drivers rather than the silicon.More info over here.