updated 01:40 pm EST, Sun December 11, 2011
AMD Tahiti details slip early
AMD's next-generation Radeon HD 7900 graphics, usually known under their Tahiti codename, have been spotted this weekend in what gives some clues as to the features inside. A large board seen by VR-Zone points to it likely having 1.5GB of RAM and a chip size similar to AMD's biggest. Although not identified by name, the part's use of two six-pin power feeds (instead of one eight and one six) may either be proof the top-end Radeon HD 7970 uses less power or else is an example of an upper mid-range chip, such as a 7950.
Further rumors may have given a clue as to the actual details. The German site 3DCenter believes that high-end Radeon HD 7000-series desktop hardware will top out at 2,048 shader (visual effects) processors, well over the 1,536 of a current 6970. It would also jump from 96 to 128 texture management units, from 32 to 48 raster units, and get a much wider 384-bit memory bus.
Clock speeds in the tip were given a range rather than hard details. The main clock would be "under 1,000MHz," while the GDDR5 memory would run at an effective equivalent of 2.5GHz to 2.7GHz. At under four gigaflops of peak performance, it would be closer to the performance of two 2.7-gigaflop 6970 boards together; a dual-chip 7990 is rumored underway that would nearly double the performance yet again. Much of the performance leap would be possible by going to 28-nanometer chipmaking processes that would keep the power comparable to the last generation.
Tips have the Radeon HD 7000-series desktop boards arriving on January 10, or virtually guaranteeing that cards would be shown off on the CES show floor in Las Vegas. Mid-range 7800 cards and the 7990 wouldn't arrive until March, but the whole range would be complete in or before spring. It's believed Apple might be hinging its next Mac Pros on having at least one of the 7900 series inside its workstations.