Radeon HD 5970 Overclocking
AMD has stated that the Radoen HD 5970 is "unlocked" and well suited to overclocking. As such, we were curious to see how much frequency headroom the Radeon HD 5970 had left under its hood. So, for our next set of performance metrics, we spent some time overclocking the new Radeon HD 5970 using the Overdrive utility built into ATI's Catalyst drivers in addition to a simple over-volting utility AMD made available for testing.
The Radeon HD 5970's stock GPU and memory clock speeds are 725MHz and 1000MHz, respectively, at 1.05v (GPU) and 1.1v (memory). With a bump in voltage to 1.1625v for the GPU and 1.15v being supplied to the memory though, we were able to take those clocks up to 860MHz and 1.22GHz.
With clock speeds that high, the Radeon HD 5970 should be faster than a pair of Radeon HD 5870 cards running in CrossFire mode, and that's exactly what we observed. With the Radeon HD 5970 overclocked, we re-ran a couple of benchmarks at 1920x1200 and the card was able to pull ahead of the Radeon HD 5870 CrossFire setup.
We should note, that power consumption went way up for the Radeon HD 5970 while over-volted and overclocked. At stock settings, the card consumed 393 watts under load, but that number jumped to 460 watts with its frequencies and voltages tweaked.