How fast will Qwen 3.5/3.6 35B A3B feel on the AMD RX 7900 XT 20GB?

Qwen 3.5/3.6 35B A3B on the AMD RX 7900 XT 20GB

Qwen 3.5/3.6 35B A3B is a 35.95B-parameter mixture-of-experts model (3B active per token). At Q4_K_M it needs about 22.9 GB of memory. The AMD RX 7900 XT 20GB has 19 GB usable, so it only fits with part of the model offloaded to system RAM, which slows it down. Expect about 122 tokens/sec (46–198), with the first token after 1.2 s for a short prompt. This estimate is projected from the hardware specs; no benchmarks exist yet.

Speed by quantization

QuantizationFile sizeMemoryGenerationFirst tokenSource
Q4_K_M22.1 GBPartial offload122 tok/s1.2 sProjected
Q8_036.9 GBPartial offload36 tok/s1.2 sProjected
FP1669.4 GBDoesn't fitWon't run——

Qwen 3.5/3.6 35B A3B on other hardware

Other models on the AMD RX 7900 XT 20GB

All models on the AMD RX 7900 XT 20GB · Qwen 3.5/3.6 35B A3B 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.