Help a newbie understand - which version for 2 x RTX 6000 Pro

#6
by peter-storm - opened

My employer recently bought a 2 x RTX 6000 Pro machine that I have access to at night - what version of this should i pick? It mentions both VRAM and system RAM - we "only" have 96 GB of system RAM available for example.

If you're talking about RTX 6000 Pro blackwell, with 96 GB of VRAM each, plus 96GB of RAM, 288GB total, then you will be able to run IQ5_KS with extreme ease and at very high speed on ik_llama https://github.com/ikawrakow/ik_llama.cpp since you have my same amount of memory after all (256gb ram + 32gb vram).

With 23.5 GB in VRAM and 214 GB in RAM I get around 15 t/s, if you keep say 173.5GB in VRAM and 64 in RAM you probably get three times the TG.

Basically, you can spread weights among memory however you want using regex (from memory):

 -ngl 100
 -ot "blk\.(?:[0-9]|[1][0-9])\.ffn.*_exps.*=CPU"
 -ot "blk\.(?:[2-3][0-9])\.ffn.*_exps.*=CUDA0"
 -ot "blk\.(?:[4-5][0-9])\.ffn.*_exps.*=CUDA1"

This puts all layers (from 0 to 100, but there's only 60 so all of them, -ngl 100) on GPU0, but then the -ot (override tensor) commands forces moe layers from 0 to 19 to CPU, from 20 to 39 to GPU0, from 40 to 59 to GPU1. Adjust however you want.

Also there are many optimizations regarding split mode, to compute tokens using both GPUs in parallel and increase TG, but that's more advanced and you can figure that out later. Unfortunately I don't have dual GPU setups so I cannot help you too much.

Thank you so much, I'll see if I can figure that out!

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