Yeah that's the upper limit I run that speed overnight while I'm not using it as it can be a little unstable if I use the PC at 1060 if I back it down to 1050 and lower the aggression to 3 and switch fastloop to true I can use the desktop and watch videos with no problems artifacts or driver recovery's. Every card is different but I would think 1000 to 1040 is achievable with a bump in core voltage and I have been running mine at the upper limit on core voltage since I got this card about 2 weeks ago.
Yea I agree with him its the upper limit but I can get between 1030-1040 before it becomes unstable on stock voltage I got really good 5830's though. I'm kind of curious how high I could push it if I up the voltage but I haven't really tried because I don't plan to use non stock voltages for long term.