Sandy Bridge motherboard. ASUS P8P67 Pro with i7-2600 processor overclocked to 4.3 MHz. CS6 Windows 7 64-bit. Mostly work in Premiere, Encore, Photoshop, After Effects. Edit HDV footage
Since I installed the GTX580, I have not tampered with the PCIe slot settings in BIOS. It is currently set to 'Auto.' There is also an X1 and an X4 mode. The manual says that the X4 setting is for high performance support, but disables some of the other ports. Is it worth going into that X4 mode? How does it compare to the X1 mode? I have no idea what any of this means. If I select X4 mode, will it make the video card run faster?
That mode only applies to the third PCI-e x16-length slot, which runs electrically at x4. It does not apply to either the first or second PCI-e x16 length slots: The first slot runs at x16 if the second x16 slot is not used, or at x8 if both the first and second x16 slots are used (the second slot runs electrically at x8).
As for the 'Auto' setting, the x4 slot runs at x1 - but it disables the x1 slot that's directly below the first (primary) x16 slot. The x1 setting enables that x1 slot but disables one of the USB 3.0 controllers (the front panel header). The x4 mode forces x4 mode on the x4 slot but disables both of the x1 slots, the eSATA controller and the USB 3.0 front panel header.