Originally Posted by Willie828
In addition to this I usually have two 6970s in Crossfire. I always suspected that my second card was broken but I only confirmed it 2 weeks ago. I ran FurMark and the second car did nothing, plugged a monitor into it and it received no signal. Definitely broken (unless its the slot that is broken).
in crossfire the 2nd card turns "slave", the dvi ports etc. are disabled, to test crossfire in furmark, run furmark in a fullscreen mode (basicly, you have no crossfire anywhere, unless you run fullscreen).
best way to test is, take one out, game till u crash, put the other card in (alone), see if you crash..
-If you dont crash first time, the 2nd card might be broken, take the 1st card out and test the 2nd card single mode.
-if you crash first time, but not 2nd time, 1st card is probarbly broken.
-if you crash with both cards in single gpu mode, its not your cards probarbly... (or you have some bad luck)
-if you dont crash single card, but you do dual card, you might have a light PSU, or crossfire causes more load on pci-e bus, controllers, cpu memory wich causes a crash.
to test ram in a real setting, take 1 ram out, if you crash the single bar is the problem, if you dont, put another bar of ram in same slot, test again, if you still dont crash, put both ram's in and test then, if you crash then.. check your ram settings, especially the voltage wich might have some drop.
occt is nice for testing cpu/gpu too, and if you run the linpack on a high setting, it will also show instability in cpu -> memory & memcontroller.