Is that still at the stock voltage (1.25v)?
Sure is, didn't have to touch the voltage. My PC has been running continuously for about 3 days without issue, temp under load hasn't changed a whole lot, seen no artifacts or anything, it's basically as stable as it was at stock.
I'm thinking of pushing it a little harder to find how high it can go with stock voltage and still be stable. I remember seeing a screenie where the guy had it running at like 4ghz at 1.25v, but I think that might have been a bug with CPU-z or something.
I have seen other people get this chip stable @ 4ghz on air cooling though, but usually the volts are upped (I think I saw one at 1.38v).