Qwen3.5 397B A17B vs Qwen3.6 35B A3B: accuracy, speed and price

• Accuracy is too close to call: Qwen3.5 397B A17B scored 32.5% and Qwen3.6 35B A3B 37.5% on the same 80 questions, a gap within what chance alone could produce.
• Qwen3.6 35B A3B is 3.6× cheaper per question as billed ($0.0037 vs $0.013), reasoning tokens included.
• Qwen3.5 397B A17B generates text 1.8× faster: 240 tokens per second against 135.
• Qwen3.6 35B A3B starts answering sooner: 0.4 s to the first token, against 0.6 s for Qwen3.5 397B A17B.

Which should you choose?

Choose Qwen3.5 397B A17B for faster streaming. Choose Qwen3.6 35B A3B for the lower cost per correct answer ($0.0099 against $0.041) and a quicker first token. The widest subject gap is in medicine: Qwen3.6 35B A3B answered 6 of 11 correctly, Qwen3.5 397B A17B 2 of 11. With so few questions per subject, treat this as a lead to test on your own prompts, not a result.

Accuracy gap -5.0 points (z = -0.66). We call a winner only when z is at least 1.96, the usual 95% threshold. Speed, latency and price need a 10% margin.