Before discussing results, let’s take a minute to briefly discuss what I consider to be a worthwhile overclock. As I’ve mentioned in past content, I’m not as interested in finding the highest overclock possible as much as I am interested in finding the highest stable overclock. To me, if an overclock crashes the computer after a few minutes of running a stress-test, it has little value except for competition.
How we declare an overclock stable is simple… we stress it as hard as possible for a certain period of time, both with CPU-related tests and also GPU-related, to conclude on what we’ll be confident is 100% stability throughout all possible computing scenarios.
For the sake of CPU stress-testing, we use IntelBurnTest, for reasons I’ve laid out in a recent forum thread. Compared to other popular CPU stress-testers, IBT’s tests are far more gruelling, and proof of that is seen by the fact that it manages to heat the CPU up to 20°C hotter than competing applications, like SP2004. Also, despite its name, IntelBurnTest is just as effective on AMD processors. Generally, if the CPU survives the first half-hour of this stress, there’s a good chance that it’s mostly stable, but I strive for a 12 hour stress as long as time permits.
If the CPU stress passes without error, then GPU stress-testing begins, in order to assure a system-wide stable overclock. To test for this, 3DMark Vantage’s Extreme test is used, with the increased resolution of 2560×1600, looped nine times. If this passes, some time is dedicated to real-world game testing, to make sure that gaming is just as stable as it would be if the CPU were at stock. If both these CPU and GPU tests pass without issue, we can confidently declare a stable overclock.
Our overclocking results for the 955 are a little brief, because I hit a cap rather quickly. The problem was simple… the CPU was overheating far too quickly, and as a result, I had to stop at 3.5GHz. While running OCCT, the test would have to halt itself within three minutes due to heat. Whether or not this was due to an incapable CPU cooler (Thermaltake V1) or not, I’m unsure, but that cooler has served us well in the past.
I can’t conclude that this is the top-overclock the chip can handle, because I’m certain it isn’t. If you have a robust cooling solution, you’ll no doubt go higher. For me, even lowering the voltages didn’t help the temperature enough, nor was that any more stable. To get this 300MHz boost though, I didn’t have to change a single voltage, at all. Overclocking made easy… stock voltage and and a low ceiling!