Crossfire formula iv cant run two cards now

[frontwave]

Crossfire IV Formula with dual 6950's in slot's 1 and 3. The other day it wouldn't post. This only happens if both cards are in the machine. When I remove the card in slot 3 it boots. When I swap that card for the one in slot 1 it works....ie both 6950's are ok. My guess is a motherboard problem....any idea people?

 

[rolli59]

If it does boot with a single card in slot 3 it is probably a PSU problem if not motherboard.