Hi! Installed GUIMiner yesterday and am fooling with BTC mining on my video crunching PC. I've an AMD FX 8320 w/ 8GB and a Radeon HD 7850 w/ 1GB. Last night I was getting a reported hash speed of around 360MH/s, whereas I'm today seeing around 260MH/s (GPU/MEM clocks unchanged). I was wondering if maybe calculation errors could be slowing it down, but there's no indication of discarded or declined shares. Any idea what could explain the drop in hash speed?
I've been trying to figure this out and was wondering if perhaps some shader pipes had failed, but there are no reported errors. I tried a complete re-install of GUIminer (including deleting the settings file), but it comes up from an idle GPU and shows the same ~266MH/s. I ran GPUID and it reports normal numbers at idle. I started mining and the load climbed to 98%, the temp to 80C, and the fan to 90%, so if pipe problems have partially shut it down, those numbers don't suggest it and if GUIminer is discarding results, I would expect it to report it, and I'm not seeing signs of share rejection in my pool account. So, maybe I was just wrong about that ~360MH/s number.
I've a second HD 7850 1GB video card and will swap that in and check the hash rate after I get the USB miner running. If anyone happens to know what the aprox hash rate should be for a 1024 shader HD 7850, please let me know!