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Comment by HarHarVeryFunny

3 hours ago

Why would you want/need to?

The advantage of HBM over regular non-stacked DRAM is memory bandwidth, which also requires a super-wide memory bus - 2048 bits wide for HBM4. Compare that to the 128 bit wide bus of a modern CPU.

So to take advantage of it on the desktop, or anywhere else, you need that 2048 bit wide bus, and a processor capable of consuming 2-3 TB of data per second!

These are not normal requirements, other than for a GPU.

SIMD (and especially the modern matrix extensions) can use as much bandwidth you can throw at it.

  • Without further clarification, that statement seems impossible. "As much" being unbounded and all. You should expand what you mean.

    • This will blow your mind, but it actually is pretty close to being unbounded. :)

      Consider the 'MMA N matrices' primitive modern CPUs are starting to support. For the current generation of CPUs, N is a constant like 16 or 32, but there's nothing preventing it from being 1024 or larger if we have more memory bandwidth.

      All this with a single instruction.

Right but if HBM memory is all that people want to produce, then building a CPU which can use it use it would be useful on it's own merits.

But in reality we also already have unified memory architecture systems, integrated graphics etc.

  • People want to produce hbm because it’s more expensive and more profitable than regular memory.

    • There is a world where scale and experience means it's about the same though, is the thing.

      And memory is already expensive. It's downright hard to even get it though - you frequently would prefer not what's cheapest, but whatever is in largest scale production.