Run Llama 3.1 405B on a Dedicated Mac

Macs that run Llama 3.1 405B

At 4-bit with a 32K-token context. Speeds are estimates; see real measurements on the calculator page.

• 2× Mac Studio M5 Ultra 256GB Cluster Best value Cluster
  2.4–3.4 tokens/sec
  from $2,399/mo Available Nov 16, 2026
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• Mac Studio M5 Ultra 512GB
  2.4–3.4 tokens/sec
  from $2,499/mo Available Dec 30, 2026
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• 2× Mac Studio M5 Ultra 512GB Cluster Cluster
  2.4–3.4 tokens/sec
  from $4,999/mo Available Dec 30, 2026
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• 4× Mac Studio M5 Ultra 512GB Cluster Cluster
  2.3–3.3 tokens/sec
  from $9,999/mo Available Dec 30, 2026
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Why it runs well on a Mac

Language models have to sit entirely in memory, and generating each word means reading through them again. Apple Silicon puts up to 512 GB of fast unified memory on one chip that the GPU can use directly, so a model like this fits on one quiet machine instead of a stack of graphics cards.

Llama 3.1 405B is a dense model: all 405 billion parameters are used for every word, so memory bandwidth decides its speed. The M5 Ultra's 1,229 GB/s makes the biggest difference here.