GLM-5.3-Flash vs GPT-5.6 Luna (Medium)
Which is better for the money: GLM-5.3-Flash by Z AI or GPT-5.6 Luna (Medium) by OpenAI? Intelligence, total benchmark cost, and end-to-end time from Artificial Analysis & other sources, snapshot 2026-10-25.
Trade-off
Verdict
Depends on your budget
GLM-5.3-Flash scores 16.8 points higher (41.8 vs 25.0) but costs 6.9× as much to run the benchmark ($306 vs $44.3; mid-range vs budget cost classes). They are not alternatives at one budget: pick GLM-5.3-Flash when you need intelligence above 25.0, and GPT-5.6 Luna (Medium) when 25.0 is enough.
| Metric | GLM-5.3-Flash | GPT-5.6 Luna (Medium) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 41.8 | 25.0 | −40.2% GPT-5.6 Luna (Medium) is 40.2% less intelligent |
| Total AA cost (lower is better) | $305.52 | $44.32 | −85.5% GPT-5.6 Luna (Medium) is 85.5% cheaper |
| End-to-end time (lower is better) | 37.69s | 6.11s | −83.8% GPT-5.6 Luna (Medium) is 83.8% faster |
| Price per 1M tokens (in / out) | $0.15 / $0.50 | $0.20 / $1.20 | |
| Input modalities | Text, Image | Text, Image |
GPT-5.6 Luna (Medium) vs GLM-5.3-Flash: 40.2% less intelligence, 85.5% less cost to run the AA benchmark, and 83.8% faster end-to-end.
Today's Pareto frontier
Against the frontier
- GLM-5.3-Flash is off the frontier: at the same or lower cost, MiMo-V2.6-Pro scores 46.30 for $207.
- GPT-5.6 Luna (Medium) is off the frontier: at the same or lower cost, GPT-6 Luna (Medium) scores 29.90 for $31.2.
GLM-5.3-FlashGPT-5.6 Luna (Medium)Today's Pareto frontierOpen-weights frontierEvery other model
Matchup
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