While the card was never 'announced' officially for a release in the the first place, the release of this dual-GPU card was expected in late July. Sources now indicate that there will be no AMD consumer product releases in August at all.  

Known under the codename "New Zealand", Radeon HD 7990 represents AMD's highest-end part from the Southern Islands architecture. Consisting out of two Tahiti XT GPUs and 6GB GDDR5 memory (special edition 7990s could reach 12GB), Radeon HD 7990 goes head to head against the GeForce GTX 690.

By default, AMD has the advantage in terms of 50% more video memory (GTX 690 has 4GB), significantly higher memory bandwidth and the new Turbo mode, technology similar to the Turbo mode used on NVIDIA Kepler-based cards with a few major differences.

We'll have to wait and see ..