The Guru of 3D posted a review on the HIS Radeon HD 7970 X Turbo edition

HIS recently released a new 'X' and X2' series of products in the Radeon HD 7900 range. They are equipped with a high performance cooler allowing them to go outside the scope of their more 'regular' products. The 4th SKU of this lineup is called the Radeon HD 7970 X Turbo edition. It pretty much is the recently released GHz concept, with the Tahiti XT2 GPU placed onto an overhauled PCB and that ICEQ X2 series cooler. The latest SKU is tagged H797QMGT3G is not even listed yet on their website ... as it's overclocked into regions we never expected of the a GHz edition. Get this, the Radeon HD 7970 X Turbo edition is boosting the GPU clock towards 1180 MHz (!)

Man a lot has changed ever since that first R7970 release back in December 2011. The initial product was launched with success and board partners all introduced customized models with factory higher clocks and within that time frame sure, there was NVIDIA with the GeForce GTX 670 and 680 releases battling against the 7900 series from AMD. The Radeon HD 7970 however is a potent graphics card with a lot of reserve, Tahiti XT2 is used on this card and yeah at 1180 MHz it is a pretty staggering product if you realize that the R7970 was released at a 925 MHz for the standard 7970.

Not only have there been tweaks on the GPU, the memory clocks got overhauled as well and have been increased from 5.5 Gbps towards 6 Gbps bringing the product a good chunk of additional memory bandwidth. Overall the new values should bring the product a nice 10 to 15% performance boost opposed to the regular model. With the release of this respin AMD will be in a better position compared to the current NVIDIA stack.

  HIS Radeon HD 7970 X Turbo Edition Review