Verdict
Built from the measurements below
- Accuracy is too close to call: GPT-5.6 Terra scored 75.0% and Qwen3.8 Max (0902) 75.0% on the same 80 questions, a gap within what chance alone could produce.
- GPT-5.6 Terra is 1.8× cheaper per question as billed ($0.0063 vs $0.011), reasoning tokens included.
- GPT-5.6 Terra generates text 2.2× faster: 101 tokens per second against 46.
Which should you choose?
Choose GPT-5.6 Terra for the lower cost per correct answer ($0.0084 against $0.015), faster streaming, shorter outputs (about 472 tokens per question against 1,722) and more hosts to choose from on OpenRouter (3 against 1). The widest subject gap is in medicine: Qwen3.8 Max (0902) answered 6 of 11 correctly, GPT-5.6 Terra 4 of 11. With so few questions per subject, treat this as a lead to test on your own prompts, not a result.
Accuracy gap +0.0 points (z = 0.00). We call a winner only when z is at least 1.96, the usual 95% threshold. Speed, latency and price need a 10% margin.