Radeon HD 7990 6GB - Overclocking

We must admit to being a bit disappointed by AMD's current lock-down of the 7990's overclocking abilities. With the release driver, we were only able to increase the core frequency by 10 per cent to 1,100MHz, bumping the card's power threshold by 10 per cent to accommodate. Perhaps more surprisingly, this had a minimal impact on in-game performance in both Unigine and BF3. The Unigine score improved just 6 points to 2177, still some way off the 2442 we managed using a pair of 7970 1GHz Edition in CrossFire, while the minimum frame rate in BF3 also rose only moderately, increasing by four per cent to 76fps at 2,560 x 1,600 with 4x AA. Whether it's power threshold throttling, poorly optimised drivers or an in-efficient PCB design, even overclocked the HD 7990 3GB isn't as quick as a pair of 7970 GHz Editions in CrossFire.