Rumor was that 4D clusters could do ~98% as much work as 5D clusters. 1920/4 = 480, and 1600/5 = 320. .98*1.5 = 1.47. Things usually don't scale perfectly and the bottleneck might be somewhere else, or the shaders might not be 1920 (that is just a rumor), hence my conservative estimate for 6970's speed. I'm definitely not saying that 6970 is 47% faster than Cypress XT although that's possibly in theory.
A lot depends on the tessellator, too. Even with all those shaders, 6970 may end up being hamstrung by its tessellator in certain games.
@busy, yeah but 256-bit bus even with 6Ghz RAM means 6970 would only have 25% more memory bandwidth than Cypress XT, so something's gotta give. Either the 1920 shader number is wrong, or 98% number, or the 2GB VRAM, or 256-bit bus, either that or AMD worked some sort of miracle in rebalancing the card or else the card is unbalanced as hell. Keep in mind that Barts seems to be memory-bottlenecked so that last possibility is real.
I smell a price war in the high-end segment in a couple of weeks. Consumers win again. :thumbsup: