I think one of my 7950's is a bit weak

I can only reliably keep them all at 1050. These weren't the best cards just xfx "double d" base models. They are located in a basement that's around 60f and not in a case still hitting 75c on the top card then a couple degrees lower for the cards.
Did you replace the paste between the GPU and cooler? I'm using Arctic silver...
I'm not going to void my 1 day old cards for a possible decrease in temps yet

they all have little void stickers on the screws. I have as5 sitting here waiting for when I get brave.