TheThreadsThatBindUs
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Mainly because Matt has stated that some expectations here (15TF, 32GB RAM etc) should be tempered.
At this stage even Matt isn't going to know PS5/XBN GPU clocks required to calculate final single precision floating point performance.
So the emphasis on banding around TF numbers and RAM amounts is a bit of fools errand. I highly doubt that Matt knows more than us about Navi's expected power efficiency at this stage, so being able to take a conclusive view on how much GPU and CPU can be included within a typical console TDP, and at what clocks, on a 350mm² APU @ 7nm is extremely difficult.
I admit that I don't really know what Matt knows, and I agree that his cautioning tempered expectations is probably the right approach, however, I would argue that even Matt can't possibly know the final next-gen console GPU TFs and RAM capacities at this stage; since GPU/CPU clocks are the very last things to be fixed and as seen with PS4 last minute changes in RAM capacities are also a possibility.
I personally think 32GB of GDDR6 are possible on 256-bit bus in clamshell mode. With RAM prices increasing and whether devs actually need so much RAM is another issue. Next-gen console may take advantage of Vega's HBCC and include fast flash storage that the GPU can directly access, thus allowing them to stick with a smaller, less expensive RAM pool, e,g, 16GB.
On the other side, without knowing anything about Navi's power efficiency at 7nm, it's impossible say what GPU clocks will be set, however, a reasonable view of GPU Compute Units can be taken at this stage, based on the silicon footprint of CUs on previous AMD GPU gens and extrapolating for 7nm geometry within a 350mm² APU die area. I think AmyS' previous post speculating 48 CUs is a serious low-ball estimate.
I do think that 72 - 80+CUs are more realistic at 7nm, but it does depend on both the scale-ability of the Navi architecture, the choice of bus width and CPU silicon footprint (i.e. 4 Zen cores or 8).
GPU clocks are the biggest question mark and are most important in determining, based on what we can reasonably speculate on at this stage, where the final console TFLOP perf. will land.