5 GPU on 1 mobo (5 LTC bounty)

[ebmx66]

I am currently running windows 7 64bit with cgminer. I have a dual psu on a Gigabyte GA-990FXA-UD3 with 4 7970s. I am planning on running the mobo and 2 7970 and 1 7950 on the 1250w and 2 7970 on the 1050w. I can get 4 cards to show on the mobo but when I plug the 5th I can't get it to show for some reason. I have 2 7970 on the mobo and 2 7970 on powered x16 risers, and the 7950 on a powered x1 riser. I know the x1 riser works slot works when I only have 4 cards connected but can't get the 5th to read no matter what combo I use. Any help would be appreciated.

[6135870]

could be 2 things. 1) the vdrop through that riser is enough to cause and error (madeinchina) 2) you should not have any xfire bridges installed 3) I thought windows 7 only allowed max 4gpus?...install gentoo

[destroyfx]

I read that the GA-990FXA-UD5 need some wiring added to some PCI-E slop to fix theses issue, maybe it's the same for the UD3 (I have personally ordered the same board than you with 6 7970... should get it in two day..

There is the link about the mod : https://bitcointalk.org/index.php?topic=36061.0

From what I read, you need this mod for each 16X card plugged on a 16X slot with a 1X riser but it might be different.