6870 & 6970 crossfire issues? & Piggybacking PSU's

[heavyb]

Hey guys!

Yesterday I combigned 2 single card miners into one dual card miner and for the first time have had issues with cards not being recognized. The 6970 is recognized fine by the pclbm gui miner, but the 6870 will not, but is in the device manager. I am wondering if windows is just goofy because I had been running one card on this motherboard for a while and am thinking it isnt taking on the second correctly. Going to try to reinstall windows and everything with both of them in, or just switch to linux!


Second question,

I have a few 750 watt psu's sitting around and would like to piggyback them into powering cards directly, so I do not need to purchase an additional 850 or 100 watt psu for multiple cards. Does anyone have any advice on how to do that?

[gogusrl]

you don't need to reinstall windows, you just need a dummy plug or another monitor in the 6870 and then extend the desktop to the second card.