Quote from: hashrateproducts on June 01, 2013, 04:23:27 PM

Quote from: turtles on May 31, 2013, 11:51:44 PM

when I install my 5th gpu the 4th pci-e slot stops working, video card still shows up in gpu-z but without proper drivers and it wont display or mine. the pci-e LED lights up like normal and that slot works fine if im only using 4 cards.

is this a limitation of the older motherboard? its an x58 out of a dell/alienware XPS, dual core 1.86ghz xeon (Nehalem) if that matters
win7 x64 don't know if I should try another OS or not

not sure on exact motherboard specs I can find out if anyone thinks they can help

What power supply are you using? Also are all the graphics cards the same or are they a mix?

5 visiontek 6950's 2 seem to be unlocked with 1536 shaders the other 3 aren't, they came like that.
I've tested using an old 3870x2 as 5th card, same problem
all the videocards work fine separately or 2-4 at a time, im starting to think its just the motherboard

motherboard/hd/etc are powered by a pretty old 600w psu, the cards/risers are all fed from the single 175amp 12v rail of a 2100w dell power edge PSU.