Ubisoft GDC Presentation of PS4 & X1 GPU & CPU Performance

[ICStats]

ethomaz said:

Captain_Tom said:

The PS4 GPU won in that benchmark because they didn't use the X1's ESRAM, and the PS4 main memory is over twice as fast (Which made up for the X1's clock speed advantage).

I thought it won because they tested GPGPU (GPU compute) and PS4 have 8 ACEs, 64 queues for compute while Xbone only 2 ACEs, 8 queues... and of course the obvious difference in RAW power helps too (18 vs 12 CUs).

I don't think the 64 queues and ACEs make the big difference here.  Those queues will make a difference when there are a lot of different GPU compute tasks contending for the GPU.  That's unlikely the case in a benchmark like this, where they have said they have combined their work into larger tasks.

Bandwidth could be the biggest bottleneck.  The presentation talks about mapping data between CPU & GPU, so the RAM speed and the coherency features likely make a big difference.

"didn't use the X1's ESRAM" - ESRAM is a limited resource so devs have to choose if they use it for backbuffer or textures or GPU compute data.  Can't have it all, since the XB1 has 8GB of main RAM and only 32MB of ESRAM, majority of a game's data is resident in RAM and needs to use RAM bandwidth to copy to/from ESRAM.