Can the Apple M4 Max (128GB) run gpt-oss 120B?
Yes
QuantQ5_K_MVery good
Memory84.3 GBof 96 GB
Speed~90tokens/s
Yes. The Apple M4 Max (128GB) can run gpt-oss 120B fully in unified memory at Q5_K_M (very good), using about 84.3 GB of the 96 GB available, at roughly 90 tokens/second.
Try other context lengths in the calculator →Memory needed by quantization
At 8,192 tokens of context. macOS lets the GPU use about 96 GB of the 128 GB unified memory by default.
| Quant | Quality | Memory | Fits? | Speed |
|---|---|---|---|---|
| FP16 | Full quality | 234.8 GB | Too big | — |
| Q8_0 | Near-lossless | 125.3 GB | Too big | — |
| Q6_K | Excellent | 97 GB | Too big | — |
| Q5_K_M | Very good | 84.3 GB | Fits | ~90 tok/s |
| Q4_K_M | Good, most popular | 72 GB | Fits | ~106 tok/s |
| Q3_K_M | Noticeably degraded | 58.3 GB | Fits | ~131 tok/s |
| Q2_K | Heavily degraded | 45 GB | Fits | ~171 tok/s |
How to run gpt-oss 120B on the Apple M4 Max (128GB)
With Ollama installed, one command downloads and starts it:
ollama run gpt-oss:120bOllama's default download is Q4_K_M (about 72 GB here). You have room for Q5_K_M, which is very good: pick that GGUF in LM Studio or from Hugging Face.
GPUs that run gpt-oss 120B comfortably
Models that run well on the Apple M4 Max (128GB)
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