Question: what efficiency should I expect (generally)? I'm mining on a Radeon 5750. I'm getting ~27% efficiency (ATM 1820 queued, 500 accepted, and U (whatever it is) is @1.89/m). Is there any way I could improve on my situation?

I had a scantime of 8 secs on all my miners previously, increased it to 45 secs and now I achieve an efficiency of 60%+ after 24 hrs.

I will keep monitoring to see whether this affects my invalids/stales in anyway