Another source claims R700 has shared memory

[Andreas G]

Even before the launch of the R680, we knew that R700 would build on what AMD/ATI learned from R680. R700 would be a dual-GPU solution of some sort, but not much else was known at the time. Later on, stories of RV770 started to surface and its connection to R700 was debated. First, it was suggested that R700 would simply be two RV770 on one board. The exact same approach as with R680, but that was not what we were hearing. R700 would be quite different, it was suggested. Instead of having two memory buffers, one for each chip, the two GPUs shared one buffer. Exactly how that would work is still in the shadows, but recent posts supports the idea of shared memory.