GPT-5.6 Luna (Medium) vs Grok 4.6 (Xhigh)
Which is better for the money: GPT-5.6 Luna (Medium) by OpenAI or Grok 4.6 (Xhigh) by SpaceXAI? Intelligence, total benchmark cost, and end-to-end time from Artificial Analysis & other sources, snapshot 2026-10-26.
Trade-off
Verdict
Depends on your budget
Grok 4.6 (Xhigh) scores 19.2 points higher (44.2 vs 25.0) but costs 51× as much to run the benchmark ($2242 vs $44.3; flagship vs budget cost classes). They are not alternatives at one budget: pick Grok 4.6 (Xhigh) when you need intelligence above 25.0, and GPT-5.6 Luna (Medium) when 25.0 is enough.
| Metric | GPT-5.6 Luna (Medium) | Grok 4.6 (Xhigh) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 25.0 | 44.2 | +76.8% Grok 4.6 (Xhigh) is 76.8% more intelligent |
| Total AA cost (lower is better) | $44.32 | $2,241.91 | +4958.5% Grok 4.6 (Xhigh) is 51× more expensive |
| End-to-end time (lower is better) | 6.64s | 47.23s | +611.3% Grok 4.6 (Xhigh) is 611.3% slower |
| Price per 1M tokens (in / out) | $0.20 / $1.20 | $2.00 / $6.00 | |
| Input modalities | Text, Image | Text, Image |
Grok 4.6 (Xhigh) vs GPT-5.6 Luna (Medium): 76.8% more intelligence, 4958.5% more cost to run the AA benchmark, and 611.3% slower end-to-end.
Today's Pareto frontier
Against the frontier
- 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.
- Grok 4.6 (Xhigh) is off the frontier: at the same or lower cost, Claude Opus 5.5 (High, Default Fallback) scores 53.60 for $2172.
GPT-5.6 Luna (Medium)Grok 4.6 (Xhigh)Today's Pareto frontierEvery other model
Matchup
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