Im having a problem with 5850 and 6850. Just installed them properly, 5850 @ 900MHz, 6850 @ 850, both running guiminer (phoenix), 5850 was 350Mhash/s and 6850 was at 220Mhash/s, but after about 2h, 6850 slowed down to 80Mhash/s, without flags its even worse (65mhash/s). I cant get it to return to its full speed.
OS - win7 pro 64
psu corsair vx550
gpu driver ver. 11.5
temps are below 80C
if I stop minig with 5850, 6850 is still working at 80mhash/s. Why did work fine for only 2h? :>
Any help is appreciated, if any more details are required I'll post them in ca. 10h.