We would like to thank the following companies for supplying and supporting us with our test system hardware and equipment: Intel, ASUS and Corsair.

On the testbed side of things there's nothing out of the ordinary and everything should be fairly self-explanatory. On the comparison side of things the main thing we want to look at is how overclocking CrossFire performance compares to stock CrossFire performance. Along with that we've also included our three-way CrossFireX results to see if we're able to close the gap much when it comes to performance.

We've also got the single HD 7970, HD 6990 and the GeForce GTX 580 from NVIDIA. Before we get into the performance side of things we want to look at how we went with overclocking. Firing up our trusty Afterburner utility we're able to adjust our voltage on the GPU to 1.299v and then proceed to bump the core and memory clock speeds up.

Looking above you can see the clocks we ended up running at. We pushed the core on each card up 150MHz to 1075MHz while the 3GB of GDDR5 on each card was pushed up a massive 1100MHz QDR bringing the final memory clock in at 6600MHz QDR.

This is a nice boost in performance that is timed two thanks to being in CrossFire. Let's see just what kind of performance this overclocked setup brings us while also finding out what goes on in the heat, noise and temperature department.

Let's get started!

The FPS Numbers Explained

When we benchmark our video cards and look at the graphs, we aim to get to a certain level of FPS which we consider playable. While many may argue that the human eye can't see over 24 FPS or 30 FPS, any true gamer will tell you that as we climb higher in Frames Per Seconds (FPS), the overall gameplay feels smoother. There are three numbers we're looking out for when it comes to our benchmarks.

30 FPS - It's the minimum number we aim for when it comes to games. If you're not dropping below 30 FPS during games, you're going to have a nice and smooth gaming experience. The ideal situation is that even in a heavy fire fight, the minimum stays above 30 FPS making sure that you can continue to aim easily or turn the corner with no dramas.

60 FPS - It's the average we look for when we don't have a minimum coming at us. If we're getting an average of 60 FPS, we should have a minimum of 30 FPS or better and as mentioned above, it means we've got some smooth game play happening.

120 FPS - The new number that we've been hunting down over recent months. If you're the owner of a 120 Hz monitor, to get the most out of it you want to get around the 120 FPS mark. Moving from 60 FPS / 60 Hz to 120 FPS / 120 Hz brings with it a certain fluidity that can't really be explained, but instead has to be experienced. Of course, if you're buying a 120 Hz monitor to take advantage of 3D, an average of 120 FPS in our benchmark means that in 3D you will have an average of 60 FPS, which again means you should expect some smooth gameplay.