Only issue is that Claymore can't read their temps/fan status.
Here's my findings from them:
http://forums.anandtech.com/showpost.php?p=38325714&postcount=1361
http://forums.anandtech.com/showpost.php?p=38325827&postcount=1368
http://forums.anandtech.com/showpost.php?p=38325893&postcount=1370
http://forums.anandtech.com/showpost.php?p=38325927&postcount=1375
How much are you taking out of them?
Between 73MH/s and 75MH/s for the three at 950MHz/900mV underclock/undervolt. Going to play with the VRAM tomorrow. At that clock they don't lose anything from stock and the temps dropped dramatically for me.