In a perfect world, maybe.Originally Posted by ORBR
this is false my friend
each chip write different data on its bus, and you're sure they read the same ONLY if they work on the same (doubled in each memory bank) framebuffer
with AFR they can read slight different assets
and with crossfire you have doubled not only bus and shaders, but buffers TOO, making the way the bus works more efficient
finally I can consider two 256 bit bus as powerful as one 512 bit bus
You see, both GPU's have to store the same information, EVEN IF IT'S AFR mode! Why? Because 99% chance says Frames 1,3,5,7,9, and 11 have 90% the same information(textures, shaders, etc) as 2,4,6,8,10, and 12.
You see, when you run multiple cards, both cards must have all the information in their individual memory banks, as both cards are likely to be showing the same textures as one another, as well as the same shaders. As such, you're effectively doubling the same exact info in both physical memory, as well as using the memory bandwidth of both cards to perform identical tasks. Seeing as how they can't share the same information from the same set of ram, they're effectively doing the same job twice.
As such, it's the same as a single 256bit memory bus, and a single set of 512mb of ram. That's why most stores make sure to specify 256bit x2 and 512mb x2. 2x256bit doesn't equal 512bit.
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