I'm mining with 6x Gigabyte Windforce OC 3GB (Samsung)
Runing them on:
TDP 67%
Temp 69c
Core -100
Memory +950
They seem stable so far keeping just above 25 Mh/s eth on claymore dual miner. I thiink it's not quite the sweetspot, but I like the consistent 150 Mh/s combined with total draw from the wall 560 watts. They also run quite cool - under 50c with 60-65% fan.
Same card but with slower Hynix memory is rock solid with nice hashrates in all algos at +140GPU/+540MEM/80%PL ... For a few algos you can even drop mem -300.