When I said I was going to post detailed Unigine Heaven results, I lied. I ran 3DMark 11 instead, since my data set for Heaven was flawed and inconsistent. I ran the numbers at stock clocks as a baseline and varied core clock in increments of 20 MHz, and memory clocks in increments of ~200 MHz. Since I’m not positive +600 MHz is completely stable, I tested at +200, +400, and +550 MHz.
All runs here are with a 100% power (TDP) ceiling. You can see that the card is running into it’s programmed thermal limits at the upper end, as the scores just barely show signs of flattening out. The max score here is 2706. Enabling 114% TDP allows for better scaling, since the card is less conservative in throttling back. The max score then is 2802 (I didn’t re-run all the test cases at 114%).
Obviously I’m going to be running wide open at 114% TDP. The benefits of overclocking in 3DMark11 is about 9.2%, slightly more generous than Heaven would suggest. But in the end, the only real benchmark that matters is how you’ll actually be using the card, and unfortunately Battlefield 3 doesn’t have a built in tool for that.
Your mileage may vary, but you can’t argue with free performance. If you haven’t OC’ed your graphics card yet, it’s worth a shot. Especially if you have the thermal overhead afforded by a non-reference cooler.