According to news leaked online, it would appear that AMD plan on releasing their dual GPU HD7990 in June. This will be going head to head against the Nvidia GTX690, a dual GK104 design.
Donanimhaber.com posted information which claim that AMD are going to wait until June, making an official announcement at Computex 2012, starting in Taipei on June 5th. Information on the HD7990 has been kept strictly internal within AMD.
The post details that the HD7990 should be based around two Tahiti GPU’s, which would mean 4096 stream processors (2×2048) and a staggering 6GB of GDDR5 memory (2x3GB). The card clocks may need to be balanced to compensate for the heat from a single PCB design, but it is all speculation right now.
Kitguru says: Nvidia will release their GTX690 first, giving AMD time to ensure that the HD7990 will outperform the competing part.