I was actually thinking about RDRAM myself
well most of the P4's that have hyperthreading have an 800 MHZ FSB, all but the 3.06 GHZ which has a 533 MHZ FSB and the ONLY M/B ive found that supports RDRAM is the GA-8IHXP and that doesn't support an 800 MHZ FSB, only 533/400 MHZ
the P4 with 3066 MHZ is less expensive than the P4 with 3000 MHZ but only by about $10-$20
RDRAM is faster, but DDR is probbably more efficient and there are not many retailers that sell RDRAM
don't expect to find a stick of RDRAM for close to the price of DDR RAM
if you find another M/B that supports RDRAM could you tell me so that i know