Tom's Hardware Guide Mainboard Guide:
Tom's Hardware Guide Mainboard Guide: DDR400 Kills Rambus: Shooting Star SiS 648 for P4 - Conclusion: SiS 648 Surprises with DDR400 and AGP 8x
It seems like getting the DDR400 plus SiS 648 is going to be the highest performance route. Seet he notes below...
The signs are auspicious - SiS might be able to land a great hit on the market with its 648 chipset. Compared to its competition (Intel and VIA), the manufacturer leads the way with numerous advantages: the 648 offers modern functions such as DDR400 support and AGP 8x, which are not to be found at all with its competitors.
Intel isn't even planning to tackle DDR400 support and AGP 8x until the start of next year. In addition, the Intel 845G chipset is only meant for DDR266 at the moment, followed by DDR333 in August.