sounds weird. i have the same card. on a maximus with a q6600 clock in at 3,6ghz. I am using a 6pin+8pin arrangement though. I got 3dm06 18643 as my highest run on 900mhz core on the card.

Check to see if there is no driver left from your old cards, seated right in the PCIEX slot. or if you can try another PSU it may help.

heres the link to my benchmark
http://www.xtremesystems.org/forums/...d.php?t=177043

at stock with those cpus minimum should be 13-14k