We have a solution for problems that we have had with A8R-MVP motherboard and two graphic cards. ATi key motherboard designer John Bruno told us that a single rail PSU is better than a multi rail PSU. He reported that ATI had some issues with multi rail PSUs while all of the single rail 500 W + PSUs were running fine. It turns out that both OCZ Power stream 600 W PSU and Akasa 650W PSU are using more than one power rails.
We got a nice link where one of the top overclocker, our good friend Sampsa had the same problem with 600W multi rail PSU and A8R-MVP board and two X1900 cards in Crossfire. He solved its troubles by switching to a single rail 560W PSU.
This specific problem reminded us on the same problem that we had with two Geforce 7800 GTX 512 cards. Those two cards in SLI were crushing the machine while two 7800 GTX 256 MB cards worked flawlessly. Someone simply could suggest that we should try single rail PSU 500+ W and everything should work. SLI works with two 7800 GTX 512 after all.
Hurray, now we know that Nvidia and ATI should warm people that they need single rail PSU not just any 600 W PSU. That really makes the difference. We are speechless why no one warned the users about this issue.
Izvor:
Inquirer