Asus Maximus IV Gene-Z Motherboard Review

The Ninjalane 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.

Index: 2.50
Optimized: 2x
Max Support: 2x

NVidia SLI
AMD Crossfire
Lucid Virtu

As indicated by the PCI Express layout chart there are only two 16x PCI Express slots on this motherboard and not much else.  This isn't much of a surprise given the 4 slot maximum allowed by the MicroATX form factor spec which tends to limit your options.  Slot 1 is the primary video card slot and will run with full bandwidth until slot 3 is populated with a device.  Once that is done the bandwidth will split between the slots with 8x dedicated to each.
 
For the best video performance you will want to populate slot 1 first followed by slot 3 if you choose to enable multi GPU.  Also keep in mind that with the Z68 you do have the option of using the Lucid Virtu technology which allows you to combine the power of discrete graphics with the internal Sandy Bridge GPU.  The technology works to redirect the discrete video output thru the integrated connection when the 3D clocks are enabled.  The integrated GPU takes over once 2D mode is enabled to conserve power.

While you can't combine the integrated GPU with a discrete graphics adaptor you can do your part to save a few bucks on your power bill by using them together.  If you ever wanted to disable this feature simply pull up the Lucid control panel and turn it off.

Just don't forget to switch your video outputs.