Quote Originally Posted by Kai Robinson View Post
A single PCIe 1.0 16x slot provides 4GB/sec of bandwidth, and a single PCIe 2.0 16x slot provides 8GB/sec of bandwidth....P45's having PCIe 2.0 8x/8x setup for crossfire is the same as having a pair of PCIe 1.0 16x slots, as each PCIe 2.0 8x provides 4GB/sec of bandwidth, correct?
That is correct, along with increased power delivery at the slot with the v2.0 spec.

As for the abnormal P45 performance I don't know what to make of that. I hope its merely a driver problem as I doubt that these cards would be over saturating the bus ( haven't done the math ) but it might be possible. If thats the case this sucks as you'd think the 4850s would be a very popular entry level crossfire option on a P45 board. I'd wait for some more numbers like you said before we panic though. I'm sure someone on the boards here has 2 4850s on a P45 already.