Yeah I have semprons, but I was wondering, do you think they get bottlenecked at all when mining? Seems the machine is less stable due to the cpu load. I've checked into making sure I have the right catalyst drivers, etc. and the cpu still runs at 60-70% load. I know from previous experiences with overclocking, that sometimes the CPU can keep you from reaching higher clocks.
There is a 45 watt dual core AMD that seems it might be better for a more stable and usable machine in terms of being able to navigate while in the linux environment. Once my miners start running, I really can barely move the mouse around or I get a lock up. Just a thought.
I have my cards at 850/300 right now, it might just be that one of my cards really can't handle those clocks.
I also wonder how much people have messed with the aggression settings in phoenix miner. I have mine set at 7 right now, but it seems it gets unstable when higher. I was thinking about downclocking one of my cards and then raising the aggression to see if there's a sweet spot for max, stable hash rate.
It would be nice to start a thread that is pinned to the top of this forum where everyone can put in their hardware set-ups and post settings with hash rates, etc.
850 is probably a bit much on stock voltage unless you have really good cooling. Try 800 and see if it's still unstable.
I have one Win 7 rig with 3x 5970s and after a lot of monitoring and tweaking I found that one of the GPUs does not like to run any higher than 880mhz, no matter how much I undervolt the ram or overvolt the GPU. The temps are fine but it still throttles so it's very likely to be the VRMs running too hot, even at 300mhz. I just run that GPU at 850/1.10v and it's stable and the other 5 GPUs are running at 900mhz/1.15v and sit around 70C. It's getting ~2450mh/s in cgminer running -I 9 and pulls about 1160 watts off the wall with the fans at 100% plus 3 additional external fans and i3 processor.
I am getting ready to wipe the OS and run linux on it. I will probably run 775mhz per core on stock voltage. In the long run, the extra strain of getting a "max hash" just doesn't seem worth the noise/power/longevity of the hardware. Then again, 5970s are $299 new and will only continue to drop in price...