Stefan Mileschin

The technology incorporated inside the R9 390 GPU is not new but is based on the Hawaii (now baptized Grenada), with the same shader count, texture units, ROPs and so on. The manufacturing process is also still 28nm but there are minor improvements which allow running the card at higher speeds and the memory quantity has been doubled, from 4GB to 8GB. Since the HIS R9 390 IceQ X2 is marketed as a pre-overclocked card, the GPU clocked has been raised to 1020MHz instead of 1000MHz stock, while the memory clock remains the same as the OEM AMD cards.

http://www.madshrimps.be/articles/article/1000751/