Quote from: Afros on December 28, 2013, 04:25:10 PM

First of all, put on top of your .bat file (in case you are using a .bat file to launch cgminer of course) the following two lines :

setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1

I had the same problem with my rig and it solved it.Now i'm happily hashing at 760/card

Yeah I already got those 2 lines on OS boot, still not able to go over 610/card, Win7 64bit btw.

I gave up a week ago trying to mine at more then 610khash per GPU after 3 days of testing but I didnt find any solution, I tried to put 1 card on the pcie bus directly too without risers to see if that was the problem, but doesn't change nothing so I don't have any other clues...

Maybe I simpy got crap GPU's that cannot run at high TC or intesity, models are Sapphire Vapor-X OC R9 280X.