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Can the Apple M1 Max (64GB) run gpt-oss 120B?

Apple M1 Max (64GB) × gpt-oss 120B8K context
Yes, with heavy quantizationFits only at a low-quality quant
Memory at Q2_K44.7 GB of 48 GB
Weights 43.8 GBKV cache 0.3 GBRuntime 0.6 GB
QuantQ2_KHeavily degraded
Speed~125tokens per second
Max context94Ktokens that fit at Q2_K
  1. FP16
  2. Q8_0
  3. Q6_K
  4. Q5_K_M
  5. Q4_K_M
  6. Q3_K_M
  7. Q2_K

Only just. gpt-oss 120B fits on the Apple M1 Max (64GB) at Q2_K, which costs noticeable quality. Expect about 125 tokens/second. A card with more memory is a better experience.

Try other context lengths

Run it with Ollama

Ollama's default gpt-oss:120b download is Q4_K_M, which needs about 71.7 GB, more than the 48 GB available. Download the Q2_K GGUF instead (LM Studio lists quants per model), or try a smaller context length.

New to this? Step-by-step setup for the Apple M1 Max (64GB)

Run it in the cloud

Want full quality? Run gpt-oss 120B on a bigger rented GPU.

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Memory needed by quantization

At 8,192 tokens of context. The black line marks the 48 GB the Apple M1 Max (64GB) can use. macOS lets the GPU use about 48 GB of the 64 GB unified memory by default.

QuantQualityMemoryFits?Speed
FP16Full quality234.5 GBToo big—
Q8_0Near-lossless125 GBToo big—
Q6_KExcellent96.7 GBToo big—
Q5_K_MVery good84 GBToo big—
Q4_K_MGood, most popular71.7 GBToo big—
Q3_K_MNoticeably degraded58 GBToo big—
Q2_KHeavily degraded44.7 GBFits~125 tok/s

Measured speed from real Apple M1 Max (64GB) owners

Tokens per second that people measured on their own Apple M1 Max (64GB), next to our estimate.

No one has measured gpt-oss 120B on the Apple M1 Max (64GB) yet. The speeds above are estimates. Run the benchmark and yours becomes the first real number on this page.

Have an Apple M1 Max (64GB)? Add your real speed

One command times gpt-oss 120B in your own Ollama, shows you exactly what it would send, and asks before sending anything. No sign-up, no personal data.

macOS and Linux

curl -fsSL https://gpufit.dev/bench.sh | sh -s -- gpt-oss:120b

Windows (PowerShell)

$env:GPUFIT_MODEL="gpt-oss:120b"; irm https://gpufit.dev/bench.ps1 | iex

How the benchmark works

GPUs that run gpt-oss 120B comfortably

Check RTX PRO 6000 Blackwell prices

Models that run well on the Apple M1 Max (64GB)

Frequently asked questions

Can Apple M1 Max (64GB) run gpt-oss 120B?

Only just. gpt-oss 120B fits on the Apple M1 Max (64GB) at Q2_K, which costs noticeable quality. Expect about 125 tokens/second. A card with more memory is a better experience.

How much VRAM does gpt-oss 120B need?

About 71.7 GB at Q4_K_M with 8,192 tokens of context, and about 234.5 GB at full FP16 precision.

How fast is gpt-oss 120B on the Apple M1 Max (64GB)?

Roughly 125 tokens per second at Q2_K, estimated from the Apple M1 Max (64GB)'s 400 GB/s memory bandwidth.