AMD confirmed at its Financial Analyst Day that the dual-GPU Radeon HD 6990 "Antilles" graphics card has been delayed to Q1 2011.
On the slide listed above, you can clearly see that Cayman, successor of Cypress [HD 5800 Series] is going to arrive on market as AMD Radeon HD 6950 and HD 6970. Given the history of the company, these two will be joined by HD 6930 as an OEM and low-volume retail part made from the GPUs that failed to "make the grade" [just like AMD Radeon HD 5830, GeForce GTX 465 and so on].
The successor of Hemlock [dual Cypress GPU] Radeon HD 5970 is currently known under codename "Antilles" [dual Cayman GPU]. When it arrives on market in first quarter of 2011, the board will receive the name AMD Radeon HD 6990.