OCC has published a review on the PowerColor PCS+ 5770
A quote from the article:
>> PowerColor PCS+ 5770 Review
The graphics card was already factory-overclocked, but I was able to take it from 875MHz core and 1225MHz memory to 940MHz core and 1340MHz memory - approximately 7.4% and 9.4% overclocks, respectively. Not humongous gains, but gains nonetheless.
>> PowerColor PCS+ 5770 Review
