Is the Mac Studio with M2 Ultra good for local LLMs?

With 192 GB it runs 49 of 73 open models well, up to MiniMax M2.7, and writes about 189–337 tokens a second with gpt-oss-20b. The M2 Ultra reads memory at 800 GB/s, which sets how fast it writes.

How much memory should a Mac Studio with M2 Ultra have for AI?

With 64 GB it runs 39 open models well; with 192 GB, 49, up to MiniMax M2.7. Memory decides which models fit, and it can’t be upgraded later.

Mac Studio M2 Ultra for local AI: which LLMs it runs, by memory

By memory size

Memory	Run well	Biggest that runs well	gpt-oss-20b
64 GB800 GB/s	39	Nemotron 3.5 Bolt 74B A9B	189–337 tok/s
128 GB800 GB/s	47	Qwen3.5 122B A10B	189–337 tok/s
192 GB800 GB/s	49	MiniMax M2.7	189–337 tok/s

Models: Mac Studio (2023). Not every memory size is offered with every model; Apple’s Tech Specs list what each one comes with.

Questions

Is the Mac Studio with M2 Ultra good for local LLMs?: With 192 GB it runs 49 of 73 open models well, up to MiniMax M2.7, and writes about 189–337 tokens a second with gpt-oss-20b. The M2 Ultra reads memory at 800 GB/s, which sets how fast it writes.
How much memory should a Mac Studio with M2 Ultra have for AI?: With 64 GB it runs 39 open models well; with 192 GB, 49, up to MiniMax M2.7. Memory decides which models fit, and it can’t be upgraded later.

Other Macs

The Mac Studio with other chips:

Other Macs with the M2 Ultra:

Mac Pro M2 Ultra

Head to head:

The M2 Ultra for local AI · The best Mac for local LLMs · Every Mac

How it’s worked out

Memory: the model’s parameters at 8, 6, 4, 3 or 2 bits per weight plus MLX’s group scales (half a bit per weight), or its native format, with room for the context on top. By default macOS lets the GPU use about 75% of unified memory. Speed: memory bandwidth divided by the bytes read per token is the ceiling for one conversation; in llama.cpp’s public Apple Silicon benchmarks real runs reach about 45% to 80% of it, which is the range shown. These are estimates, not measurements: measure your own Mac on MLX Bench. Model figures from each official model card, chip figures from Apple’s Tech Specs. Checked 2026-10-19. Same data as mlx.app/compare.