I bought 3 7970 DirectCU II cards for use in tri fire; however, I'm getting the same performance with all 3 cards as I am with just two.
I'm running a 2600k @ 4.8GHz on a Maximus IV Extreme-Z board and 8GB RAM @ 1600MHz with a Corsair AX1200 PSU. I'm on 12.6 WHQL drivers currently. I've tried running each card in different slots, with one or all 3 monitors connected, and still no luck getting anymore performance.
One of the 3 cards shows a lot more information under GPU-z than the other two, such as amperage, wattage, VRM temp, etc. The other two only show VDDC, GPU diode temp, and memory usage. The card that shows more info also seems to be stuck at ~1.06V whether under load or idle, while the other two go from 0.85V at idle to 1.175V under load.
I'm thinking of RMA'ing the odd-card-out and seeing if a replacement will fix this. Can anybody offer any help with this?