GPT-OSS 120B is a 116.83B-parameter mixture-of-experts model (5.1B active per token). At MXFP4 it needs about 64.1 GB of memory. The Mac Mini M4 Pro 64GB has 48 GB usable, so it doesn't fit, even at its smallest quantization.
| Quantization | File size | Memory | Generation | First token | Source |
|---|---|---|---|---|---|
| MXFP4 | 63.4 GB | Doesn't fit | Won't run | — | — |
All models on the Mac Mini M4 Pro 64GB · GPT-OSS 120B on all hardware
Estimates for a short prompt on a single device. Measured numbers come from community benchmarks (r/LocalLLaMA, localscore.ai and more); others are derived from similar setups or projected from specs. Open source on GitHub.