PCI-e x16 vs. PCI-e x8

[sterling013]

Looking at mother boards, I noticed that though they have two or three PCI-e x16 slots, the specifications note that the second slot(s) only run at x8 or less in SLI or Crossfire. I am looking at putting together either a i7-920 or Phenom II X4 955 Black Edition system with two GTX 260 Core 216 in SLI or HD4870 in Crossfire (or better) cards. Will the x8 PCI-e slot reduce the performance of the second card? I do not want to spend all that money on a second card and not get the most out of it. Is it worth the Premium price for a motherboard that has x16 in all PCI-e slots in SLI or Crossfire? I could not find a definitive answer in the forums. Your opinion will be appreciated. THANKS! Sterling

 

[r_manic]

Practically all cards are specified as working with only specific kind of PCIe slots. Yes, it's possible to put an x16 card into an x8 card, but that will bottleneck the card. Worse, if you're doing SLI or CrossFire, if it's possible to do it on different kind of slots in the first place, you also won't maximize the performance.