Thanks for the follow up NameTaken! What bios do you use?
Spinx, I am very interested to know if you changed anything beside going with these parameters. And if you mine in Win7 or Linux.
Im mining with BAMT-1.4.1 by "honeybee", easy as pie

(
https://litecointalk.org/index.php?topic=2924.msg116877#msg116877)
Besides lowering the powertune values on some of the cards, and adjusting "gpu-fan" to "50-100" i have not changed anything, you should do be aware that all cards are different and same brand/settings does not equal same hash speed :/