On SLI mobos (or Crossfire) can the lower PCI-E slot be used as main?

[unreal]

As the title reads, because I have a choice;

M-ATX motherboard, or something like an Asus SLI mobo providing the lower PCI-E card can be used by itself, so the one above it is empty. Why? Well I don't want it to feel like showing off so I won't say, but it's nothing major.

Thanks in advance

[demonwolf]

You can use the lower pci-e slot in place of the top one. I think you have to enable the jumpers to sli configuration then place your graphics card in the lower slot. The downside to this is that it will only be running in 8x pci-e mode while a single card in the top slot works at 16x.

[unreal]

Ah thanks then - I doubt I will be losing much performance with this then. Do you know that for sure?

[unreal]

Sorry for the bump, but is there no one else who can confirm this?

[demonwolf]

Well I learnt this over at the dfi street forums
heres a link to one thread where someone has run his graphics card in the lower slot and people tell him that itll run at pci-e8x and not 16x

http://www.dfi-street.com/forum/show...ght=pci-e+slot

[Rave]

Yeah, it'll deffo run at PCI-8X (unless you get the new Asus board which has 16 lanes for each slot). Should be barely any performance penalty though.

[unreal]

Oh thats good then I will do that.... I will see what full ATX motherboard I can get now that supports SLI. Many thanks, the answers were MUCH appreciated