That's a pretty nifty little motherboard... something you can probably try pretty easily is to use the switches to enable or disable specific PCIe slots. (Also make sure they are turned on, but I doubt they would do anything if they were turned off.)

http://www.guru3d.com/article/asus-r...treme-review/6

Very simple, these are there to en/disable the corresponding PCIe slots. Weird and unusual you might think, but if one of the PCIe x16 cards is out of order during massive cooled down OC session, you can simply disable it without the need of removing the cards (which typically have LN2 pots sitting on them).