How fast will local models feel on the AMD RX 7900 XT 20GB?

Local LLM speed on the AMD RX 7900 XT 20GB

The AMD RX 7900 XT 20GB has 20 GB of memory and 800 GB/s of memory bandwidth, which is what mostly decides generation speed. Below is the expected speed for each model at the best quantization that fits.

Model	Quantization	Memory	Generation	First token
Qwen 3.6/3.8 27B	Q4_K_M	Fits	30 tok/s	0.5 s
GLM-5.3 Flash	UD-IQ1_S	Doesn't fit	Won't run	—
GPT-OSS 20B	MXFP4	Fits	124 tok/s	0.3 s
Gemma 4 26B A4B	Q4_K_M	Fits	66 tok/s	0.3 s
Qwen 3.5/3.6 35B A3B	Q4_K_M	Partial offload	122 tok/s	1.2 s
Ornith 1.5 35B A3B	Q4_K_M	Partial offload	131 tok/s	1.2 s
DeepSeek V4 Flash	UD-IQ1_S	Doesn't fit	Won't run	—
GPT-OSS 120B	MXFP4	Doesn't fit	Won't run	—
Gemma 4 31B	Q4_K_M	Partial offload	26 tok/s	1.6 s
Llama 3.1 8B	Q4_K_M	Fits	102 tok/s	0.4 s
Qwen 3.5 9B	Q4_K_M	Fits	81 tok/s	0.4 s
DeepSeek R1 Distill 14B	Q4_K_M	Fits	56 tok/s	0.4 s
Ornith 1.5 9B	Q4_K_M	Fits	79 tok/s	0.4 s
Muse Glimmer 30B	Q4_K_M	Partial offload	16 tok/s	1.6 s
Qwen3 30B A3B	Q4_K_M	Partial offload	222 tok/s	1.2 s

Other 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.