PaintTinJr
Member
No, I think you misread the comment - which actually implies either amazing yields or cutting edge stacking of L2 cache and logic (temptest engine/cache scrubbers).You simply cannot "rework" a CU on the fly. They have to be DESIGNED that way. The Tempest has been shown as a separate and different entity from the GPU. In fact, it's been stated that the Tempest engine is more related to the Cell processor and SPU's than it is a simple CU.
This is basically just another attempt to try and claim the PS5 has less power than stated and that it's "really" closer to that 9TF mark that so many loved to talk about early on.
So bottom line, GPU has 40 CU's with 4 disabled. Tempest engine is a separate part of the system. So is the SSD controller for Pete's sake before someone tries to claim that "really 4 of the 36 CU's are completely taken up controlling the SSD so the PS5 REALLY only has 32 CU's available for games!" or some crap like that.
The 36CUs for the GPU is a matter of fact, and is merely one constraint along with the other info like the base CU count - expected to be 40CUs. I was highlighting that they either designed the APU to have 19 identical CU pairs (38 identical CUs) and 1 pair (2 identical reworked CUs) as the Tempest engine - so that the chip would produce a good chip so long as only 1 pair of the 19 was defective and/or so long as only 1 half of the of the Tempest engine pair was defective - thereby giving the 36 working CU count + the tempest engine, while adhering to the constraint of 40 - 2 pairs of 2.
The alternative IMHO is that the chip is either stacked - with the Tempest engine CU in a different layer, possibly with cache scrubber logic, probably between the CUs and the L2 cache if it is a 3 layer stack - or that Tempest engine CU is in addition to the 40CUs inside the GPU - which I believe is less logical.
I think the Tempest engine being inside the GPU is inferred by this Cerny Quote:
"One wavefront is for the 3D audio and other system functionality, and one is for the game. Bandwidth-wise, the Tempest engine can use over 20GB/s, but we have to be a little careful because we don't want the audio to take a notch out of the graphics processing"
My view is that if the Tempest engine was separate/external to the GPU, then he would have said it could take a notch out of the system bandwidth - cpu or GPU - not the graphics processing, as he said, but it was just some positive speculation.