The most interesting change is what’s missing: the small, on-chip RAM (ESRAM). Microsoft claims that the higher global memory bandwidth removes the need to have it on Project Scorpio.
Digital Foundry is still a bit concerned that, while the 320 GB/s bandwidth might be enough, the latency might be a concern for compatibility. Personally, I’m not too concerned. Modern GPUs do a huge amount of latency-hiding tricks, such as parking whole shaders at global memory accesses and running other tasks while the GPU fetches the memory the original shader needs, swapping it back and finishing when it arrives. Also, the increased GPU performance will mean that the game has more room to be wasteful of GPU resources, since it only needs to perform at least as good as a regular Xbox One. I expect that there wouldn’t be enough round-trips to ESRAM for it to be a major slowdown when running on Project Scorpio (and its not-ESRAM).
Via: PC Perspective