GPT-5.6 Luna (Xhigh) vs GPT-6 Astra (Xhigh)
Which is better for the money: GPT-5.6 Luna (Xhigh) by OpenAI or GPT-6 Astra (Xhigh) by OpenAI? Intelligence, total benchmark cost, and end-to-end time from Artificial Analysis & other sources, snapshot 2026-10-27.
Trade-off
Verdict
Depends on your budget
GPT-6 Astra (Xhigh) scores 17.8 points higher (52.4 vs 34.6) but costs 21× as much to run the benchmark ($3803 vs $179; flagship vs mid-range cost classes). They are not alternatives at one budget: pick GPT-6 Astra (Xhigh) when you need intelligence above 34.6, and GPT-5.6 Luna (Xhigh) when 34.6 is enough.
| Metric | GPT-5.6 Luna (Xhigh) | GPT-6 Astra (Xhigh) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 34.6 | 52.4 | +51.4% GPT-6 Astra (Xhigh) is 51.4% more intelligent |
| Total AA cost (lower is better) | $179.33 | $3,802.98 | +2020.7% GPT-6 Astra (Xhigh) is 21× more expensive |
| End-to-end time (lower is better) | 45.86s | 176.59s | +285.1% GPT-6 Astra (Xhigh) is 285.1% slower |
| Price per 1M tokens (in / out) | $0.20 / $1.20 | $10.0 / $50.0 | |
| Input modalities | Text, Image | Text, Image |
GPT-6 Astra (Xhigh) vs GPT-5.6 Luna (Xhigh): 51.4% more intelligence, 2020.7% more cost to run the AA benchmark, and 285.1% slower end-to-end.
Today's Pareto frontier
Against the frontier
- GPT-5.6 Luna (Xhigh) is off the frontier: at the same or lower cost, GPT-6.1 Terra (Medium) scores 41.30 for $175.
- GPT-6 Astra (Xhigh) is off the frontier: at the same or lower cost, Kimi K3.1 Pro scores 55.10 for $3117.
GPT-5.6 Luna (Xhigh)GPT-6 Astra (Xhigh)Today's Pareto frontierEvery other model
Matchup
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