The current generation AMD GPU series collectivelly known as "Southern Islands" were released over a year ago, with the beginning of its rollout in January 2012. Sixteen months later, the Radeon HD 7000 series is still very much relevant, as AMD continues to release new models under the same GPU family.
Still AMD feels they need to offer an ultra-expensive graphics card as well and therefore today they are releasing the Radeon HD 7990. Although it's been over a year since they launched the Radeon HD 7970, we are just getting an official dual-GPU version, in truth they have been around for some time. Products such as the PowerColor Devil 13 HD 7990 6GB, HIS Radeon HD 7970 6GB IceQ X2 and Asus ROG Ares II have been doing the rounds for quite a while now.
The Radeon HD 7990 it takes a pair of 7970 GPUs with overclocked cores (from 925MHz to 1000MHz), while boosting the GDDR5 memory from 1375MHz to 1500MHz. These clock speeds happen to match the 7970 GHz Edition, though the 7990 doesn’t feature a Boost clock, so we feel the GPUs are better compared to the standard 7970.