[citation][nom]ab[/nom]When I asked GigaByte (pre-sale) which single slot video card(s) would allow all 7 PCIe slots to be occupied simultaneously on the GA-X58A-UD9, they did not know (or at least tell me). Any ideas?[/citation]Three of those slots are "just for looks" because the board is primarily designed for 4-way SLI. Drivers don't support more than four GPUs for SLI or CrossFire, and the NF200 bridge works best as a repeater (sending the same data to multiple cards).
Breaking SLI (or CrossFire) eliminates the repeater function, so the slots will have to share non-multiplied data at reduced performance. However, the slots ARE connected, so you should be able to run ANY single-slot cards under two conditions:
1.) The cards run cool enough to avoid overheating in that configuration
2.) The cards don't draw too much power from the slots. This isn't normally a problem, but might be a problem with the Afox 6850's we just tested. Yet those cards would probably overheat anyway.
So, if you wanted to do 7 graphics cards, they're going to have to be fairly weak, cool-running cards. Probably 5700 series or below.