Ok I was able to enable the 2nd card in the BIOS to run @ PCI-E 2.0 x 4 (no option to go higher) & can run 2 x miners in Crossfire (which restricts me to using just 1 monitor) but not separately. The second card only runs @ 100 Mhashs/s in this configuration. So it seems my PSU is ok.
But I have 3 monitors in total including my main monitor & Ive got the 2nd card plugged into 2 monitors but it doesnt see them at all (even if not running CF). I can get 1 of these monitors enabled by plugging it in to the same card that the main monitor is plugged into (and extending the desktop) but the 3rd ones not seen at all. If I swap them around it works fine also on the 2nd card so neither the card is faulty. Now I could be wrong here but arent these cards supposed to be able to run 6 monitors all up? Admittedly the 2 smaller side monitors are a few years old now but I have them coupled up to VGA-DVI adaptors and they worked fine on an old cheapy vid card I was using before. I'm thinking I could buy a splitter cable and run the 2 side monitors off the 2nd DVI port on the main card but this still doesnt get me round the fact I cant mine with both cards at the same time (except under CF). Ive seen posts on here about running 'dummy plugs' but isnt that only something you need to do if you only have 1 monitor and doesnt apply to Win 7 anyway? Kinda miffed atm..
That's only if it has the Eyefinity feature. Not every card is capable. I would only run one monitor and try dummy plugs and see what happens.