How fast will GPT-OSS 20B feel on the AMD RX 7900 XT 20GB?

GPT-OSS 20B on the AMD RX 7900 XT 20GB

GPT-OSS 20B is a 20.91B-parameter mixture-of-experts model (3.6B active per token). At MXFP4 it needs about 12.9 GB of memory. The AMD RX 7900 XT 20GB has 19 GB usable, so it fits entirely in memory. Expect about 124 tokens/sec (95–152), with the first token after 0.3 s for a short prompt. This estimate is based on community benchmarks of this exact setup.

Speed by quantization

QuantizationFile sizeMemoryGenerationFirst tokenSource
MXFP412.1 GBFits124 tok/s0.3 sMeasured

GPT-OSS 20B on other hardware

Other models on the AMD RX 7900 XT 20GB

All models on the AMD RX 7900 XT 20GB · GPT-OSS 20B 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.