To summarize GFHK's note:
Rubin's SOCAMM2 has been nerfed once again — down to 64GB.
But is that bearish? If anything, it's the opposite.
Working off a 192GB SOCAMM2 configuration, NVIDIA had asked the memory makers for a corresponding volume of SOCAMM2 — and the memory makers came back telling them they could only supply 60–70% of that volume.
This isn't a demand problem, it's a supply problem. The spec was cut because they couldn't get the SOCAMM2 supply.
What about HBM? Contrary to what a certain research house published, Rubin Ultra is not being considered with 8Hi only. An HBM4E 12Hi SKU is also under consideration.
It is a step down from the original 16Hi — but everyone already knew that, right? NVIDIA needs 12Hi if only to compete with AMD. The 8Hi is there to accommodate SKU requests from a subset of customers.