GLM 5.3 vs GLM 5.3 Flash: accuracy, speed and price

• Accuracy is too close to call: GLM 5.3 scored 67.5% and GLM 5.3 Flash 67.5% on the same 80 questions, a gap within what chance alone could produce.
• GLM 5.3 Flash is 6.4× cheaper per question as billed ($0.00015 vs $0.00093), reasoning tokens included.
• GLM 5.3 generates text 1.8× faster: 154 tokens per second against 83.
• GLM 5.3 Flash starts answering sooner: 0.5 s to the first token, against 0.8 s for GLM 5.3.

Which should you choose?

Choose GLM 5.3 for faster streaming and more hosts to choose from on OpenRouter (37 against 34). Choose GLM 5.3 Flash for the lower cost per correct answer ($0.00022 against $0.0014) and a quicker first token. The widest subject gap is in engineering: GLM 5.3 answered 10 of 15 correctly, GLM 5.3 Flash 8 of 15. 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.