Gigabyte does this so that you can run PCI Express x16 graphics card concurrently with the IGP. It uses four PCI-E lanes from the ICH South Bridge for the PEG x16 slot. If they used the native PEG x16 interface in the North Bridge, you couldn't use PEG + IGP concurrently due to chipset limitation.Originally posted by: Zap
The Gigabyte G31 chipset board is a nice one, but beware of their G33/G45 chipset boards because for some reason Gigabyte likes to make the PCIe slot a x4 electrical with x16 physical. This is an example where under specifications you can see "1 x PCI Express x16 slot, running at x4." Some other boards are like this, but Newegg's description is not always as clear, so make sure you find out before buying - ask or check Gigabyte's web site.