PCIE 8X8 VS 16X4

[cocheese256]

I am about to put together an I5 build. I see some of the revised p67 motherboards are trickling in. I plan on running either crossfire or sli. I see in the specs of a lot of mobos where it says 1 PCIe x16 (or 2 PCIe slots at x8). Other boards are showing 1 PCIe x16 and 1 PCIe x4. I see most of the two PCIE x8 boards are snatched up quickly.

Which would you recommend and/or is it that critical of a difference?
Thank you.

 

[Tsumi]

the x16/x4 boards do not support SLI, but do support crossfire. However, due to the nature of the board, crossfire on x16/x4 boards would be slower than the x8/x8. This is because the x4 lanes come from the southbridge of the chipset, which is also linked to the SATA controller, any other PCI-E x1 slots, USB ports, etc. Basically, the x4 would have to compete for bandwidth with all of your other peripherals, and it would have to communicate through the southbridge, instead of directly with the processor, in the case of the x16 card. With x8/x8, the direct x16 lane is split between the two cards, and both cards communicate directly with the processor and each other.

 

[cocheese256]

Nice explanation. So it would be better for me to wait it out and find an x8/x8 board. Thank you.