Megadrive1988
Veteran
Here's a rather interesting post by blu on another forum (guess where from
U-GPU already has access to a split-mem architecture - 32MB edram, and 2GB of main ram. The first pool likely provides BW in the hundreds of GB/s. The second pool - a couple of tens of GB/s (i.e. from mid 20's to low 30's GB/s). Now, in contrast to the 360, the edram is very likely not a 'mere' framebuffer. That means that relatively small but often-used render targets might not need to be resolved to main RAM - they can sit in edram during their entire lifespan (alternatively, some write-only targets could sit entirely in main RAM - Xenos' memexport style). Long story short, in the average main ram BW will go essentially toward static texture assets and resolved large target (e.g. deferred shading g-buffers). But all read-modify-write fb BW will be covered by edram. As shown in practice by various platforms (360 being a good example), such a split could be very beneficent toward a balanced performance.