I tried without powertune also. Tried g 2/4
Same issue.
this is a new installation of windows though. Do I have to do anything all over again in terms of windows optomization? I downloaded the new amd catalyst 14.6 beta
not sure if your problem is solved.
i did some experiments with catalyst-14.6 yesterday = 100% hw errors no matter what settings I have tried.
so i reverted back catalyst to 13-12 and everything is ok.
not sure which catalyst is the best for x13 but 14.6 is not working for my gpu's (r9 280x) and x13.
so if you still have problems try with an older catalyst.
hope this helps!
sorry for quoting myself - some additional info for amd miners:
cat. 14.4 is also working for x13 (and i guess x11) with almost te same hr as 13.12.
However hr for scrypt-n is lower with 14.4.
forget 14.6 (still beta) for x11/x13 ... only hw errors.
i will stick with 13.12 for now....
edit: miner for my tests: sgminer 4.1.0