So there seems to be a lot of discussion about exactly how many GPUs you can fit into one motherboard. One of the posters on this thread got 8 with win 7 64 bit, MSI77A-G45. However...as a noob, I note there are only 7 actual slots. Even with risers how do you get 8 GPUs to fit in 7 slots? Do you have to use at least 1 double GPU unit (e.g. 5970, 6990).
https://bitcointalksearch.org/topic/78-gpus-per-motherboard-234090
https://bitcointalksearch.org/topic/78-gpus-per-motherboard-234090
I think that is correct but I am not 100% certain. I just put one GPU per slot when I build my rigs.