Apple M2 Ultra meets the minimum VRAM requirement for Q4 inference of openai/gpt-oss-20b. Review the quantization breakdown below to see how higher precision settings impact VRAM and throughput.
Apple M2 Ultra can run openai/gpt-oss-20b with Q4 quantization. At approximately 63 tokens/second, you can expect Good speed - acceptable for interactive use.
You have 182GB headroom, which is sufficient for system overhead and smooth operation.
| Quantization | VRAM needed | VRAM available | Estimated speed | Verdict |
|---|---|---|---|---|
| Q4 | 10GB | 192GB | 62.96 tok/s | ✅ Fits comfortably |
| Q8 | 20GB | 192GB | 41.11 tok/s | ✅ Fits comfortably |
| FP16 | 41GB | 192GB | 23.23 tok/s | ✅ Fits comfortably |