ATI R600 can only manage 16 pixels per clock

@ 2006/11/15
MANY THINGS ABOUT ATI's upcoming R600 are surprising, to say the least.

First of all, the GPU is a logical development that started with the R500Xenos, or Xbox GPU, but without the 10MB eDRAM part. Unlike the Xbox GPU, the R600 has to be able to support a large number of resolutions and, if we take a look at today's massive 5Mpix resolutions, it is quite obvious that R600 should feature at least five times more eDRAM than Xbox 360 has.

DAAMIT kept the RingBus configuration for the R600 as well, but now the number has doubled. The External memory controller is a clear 512-bit variant, while internally you will be treated with a bi-directional bus double the width. The 1024-bit Ringbus is approaching.
Comment from Rutar @ 2006/11/15
ATI has made good expierence having the first strike in memory bus bitrate