Asus P5Q Pro, PCI E X16 slots

Yes.
As long as your single card is running in the top PCIe 16x slot, it will be running at full speed.



The blue slot is the one you want.

thanks

And if you add a second card, the drop to x8+x8 won't hurt that much. It's only important IMO at 1920x1200 or more, from what benchmarks I've seen.

wait, if you use one card does it matter what pci x16 slot you put it in?

Yes it does.

here is a quote from ASUS specifications

"2 x PCI Express 2.0 x16 slots, support ATI CrossFireX™ technology at x8 link
(PCIe x16_1 blue, PCIe x16_2 black*)
1 x PCI Express x16 slot at max. x4 link(black)"

So unless in crossfire mode the black will run at 4X and the blue will run at 16X

1Haplo

what iff you run 1 radeon 4800 and one sas 8x adaptor will both slots run down to 8x each or does the dual 8x only aply to crossfire

No. The problem is caused by the limited number of PCI lanes in the P45 chipset.