PCIe x16 x16 vs x8 x8 for Motherboards

[gigabytecoin]

The 5970 specifies that it requires PCIe 2.1 x16 to function.

If I buy a mothoerboard with 4x PCIe 2.0 slots - and crossfire support - will 4x5970 GPUs work for mining?

What about 2x5970 GPUs?

Basically do the x16, x8, x4 and 2.1 vs 2.0 settings bear any meaning on my motherboard?

I'm thinking of going with this one: http://www.newegg.com/Product/Product.aspx?Item=N82E16813130223

[Cryptoman]

That mobo will work fine, but I wouldn't put 4 GPUs in it because you will have difficulty keeping them cool since there is no airspace for the fans to draw in cool air.  You will either need to come up with a custom cooling setup or cram wedges between the boards (not recommended).  If I were to do a 4-GPU setup, I think I would take out the existing fans and shrouds and design a plenum that channeled the output from a high-CFM 120 mm fan into the front edges of the cards, with the exit through the slots in the PCI hanger.

Regarding the PCIe transfer bandwidth, it doesn't matter for mining. x4 even is fine really.

[error]

You could also watercool them.