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426 points benchmarkist | 1 comments | | HN request time: 0s | source
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zackangelo ◴[] No.42179476[source]
This is astonishingly fast. I’m struggling to get over 100 tok/s on my own Llama 3.1 70b implementation on an 8x H100 cluster.

I’m curious how they’re doing it. Obviously the standard bag of tricks (eg, speculative decoding, flash attention) won’t get you close. It seems like at a minimum you’d have to do multi-node inference and maybe some kind of sparse attention mechanism?

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danpalmer ◴[] No.42179501[source]
Cerebras makes CPUs with ~1 million cores, and they're inferring on that not on GPUs. It's an entirely different architecture which means no network involved. It's possible they're doing this significantly from CPU caches rather than HBM as well.

I recommend the TechTechPotato YouTube videos on Cerebras to understand more of their chip design.

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accrual ◴[] No.42179717[source]
I hope we can buy Cerebras cards one day. Imagine buying a ~$500 AI card for your desktop and having easy access to 70B+ models (the price is speculative/made up).
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danpalmer ◴[] No.42180050{3}[source]
I believe pricing was mid 6 figures per machine. They're also like 8U and water cooled I believe. I doubt it would be possible to deploy one outside of a fairly top tier colo facility where they have the ability to support water cooling. Also imagine learning a new CUDA but that is designed for another completely different compute model.
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1. initplus ◴[] No.42180442{4}[source]
Yeah you can see the cooling requirements by looking at their product images. https://cerebras.ai/wp-content/uploads/2021/04/Cerebras_Prod...

Thing is nearly all cooling. And look at the diameter on the water cooling pipes. Airflow guides on the fans are solid steel. Apparently the chip itself measures 21.5cm^2. Insane.