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by aurareturn 470 days ago
It's both compute and bandwidth constrained - just like trying to run Crysis on CPU rendering.

A770 has 16GB of RAM. You're shuffling data to the GPU at a rate of 64GB/s, which is magnitudes slower than the internal VRAM of the GPU. Hence, this setup is memory bandwidth constrained.

However, once you want to use it to do anything useful like a longer context size, the CPU compute will be a huge bottleneck for time-to-first-token as well as tokens/s.

Trying to run a model this large, and a thinking one at that, on CPU RAM is a gimmick.

1 comments

Okay, let's stipulate LLMs are compute and bandwidth sensitive (of course!)...

#1, should highlight it up front this time: We are talking about _G_PUs :)

#2 You can't get a single consumer GPU that has enough memory to load a 670B parameter model, there's some magic going on here. It's notable and distinct. This is probably due to FlashMoE, given it's prominence in the link.

TL;Dr: 1) these are Intel _G_PUs, and 2) it is a remarkable distinct achievement to be loading a 670B parameter model on only one to two cards

1) This system mostly uses normal DDR RAM, not GPU VRAM.

2) M3 Ultra can load Deepseek R1 671B Q4.

Using a very large LLM across the CPU and GPU is not new. It's been done since the beginning of local LLMs.