They are bios undervolted -150mv. I mined without problems equihash (before the fork), ethash, etc. It starts mining and then the driver crashes. I guess the UV is too much...
My rig on 6x390 mined without problems 144/5 24/7 with 6alpha2, H/r: 33-36H/s per card
Undevolt GPU customize until the frequency is stable.
Lolly, thank you VM.