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 H200 141GB (cloud) has 131 GB usable, so it fits entirely in memory. Expect about 196 tokens/sec (144–249), with the first token after 0.3 s for a short prompt. This estimate is based on community benchmarks of this exact setup.
| Quantization | File size | Memory | Generation | First token | Source |
|---|---|---|---|---|---|
| MXFP4 | 63.4 GB | Fits | 196 tok/s | 0.3 s | Measured |
All models on the H200 141GB (cloud) · 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.