Check out the review from Anand, benches the 875P chipset vs the 850E chipset.
numbers show, there really isn't much of a difference.
as quoted : keep in mind article is from 4/03
"The next milestone that's set with the 875P is that Intel has finally released a chipset to push RDRAM out of their product lineup; not that there's anything wrong with RDRAM these days, but the fact of the matter is that DDR is far more plentiful and thus much more attractive to end-users and resellers."
edge does go to the 875p chipset but not by a huge margin.
Review