Multi GPU Index
The Hardware Asylum Multi-GPU index is a portable set of data we can use to determine the multi-GPU potential of any motherboard. A higher index number indicates a favorable condition for multiple graphics cards while a lower number indicates a hindrance in one of our leading indicators. Since the Index is not dependent on system architecture it can be applied to any motherboard regardless of processor or chipset generations.
Max Support: 3x
This motherboard will support up to three graphics cards and is optimized for dual card operation.
For best video performance you will want to populate the top most PCI Express slot with your video card and try to avoid using the secondary slot. The secondary slot is in fact hardwired to 8x PCI Express lanes and only active if the slot is populated. Given the distance between the slots if you choose to enable Crossfire be sure that your bridge connector is long enough to reach.
Boards like this are really quite fun to mess with and even though the last slot is hardwired to 4x lanes you can still run a third card either as a dedicated PhysX processor or play with 3-way Crossfire. The best option would be to reserve it for hardware RAID controllers or leave it open for better dual card cooling.
Many of you will have noticed the metal covers over the PCI Express slots. The intent of these metal covers is to reinforce the PCI Express slot and prevent them from breaking. Typically the slot is a friction connection made from the pins sitting in the plastic connector. By adding these metal covers the slot now has a mechanical connection to the motherboard via solder points that will prevent pulling the slot up and splitting the slot from sideways pressure.
Bottom line, they made the plastic stronger. There is also a rumor that the metal will also block EMI which might be a future problem with PCI Express 8.5 but who really knows.