I have a computer with mother board ASUS’s P5K. This board has two PCI-E x16 slots but one of them seems only work at X4 mode (2 x PCI-E x16 (blue @ x16 mode, black @ x4 or x1 mode) . Can I put another 8600 or 8800 card on this slot? Will the card on this slot work? I don’t want to use SLI. Thanks!