PCIe Lane Management

[DPete27]

I thought of a question about PCI-Express lane management and although its really bugging me to know, I just dont have the time to look it up (and a quick google search didn't turn up anything). Here goes:

I know that motherboards can run PCIe x16 or PCIe x8/x8 and so on and so forth with graphics cards. But what happens to the PCIe lane distribution on a mATX board like this one for example with three PCIe x16 slots and one PCIe x1 slot if I were to have a single graphics card and populate the rest of the slots with only PCIe x1 or x4 expansion cards? Does the graphics card still run at x16 or does it drop down to x8?

I know that even high end graphics cards can barely take advantage of 8 PCIe 2.0 lanes let alone PCIe 3.0, but I'm just curious.

[Krogoth]

That motherboards looks like its meant to be paired with a Ivy bridge in order to use those PCIE slots at 3.0 mode . If you throw in a Sandy Bridge chip, they revert to PCIe 2.0 mode, since the PCIe controller is on the CPU not on the "northbridge".

[DPete27]

@Krogoth: I'm planning on an Ivy Bridge upgade

[BobbinThreadbare]

It's been my experience that the extra slots are usually x1 slots unless you change a bios option for dual x8 mode. I can't say that's how this board specifically works though.