GPT-6 Luna (High) vs Step 5 Preview

Which is better for the money: GPT-6 Luna (High) by OpenAI or Step 5 Preview by StepFun? Intelligence, total benchmark cost, and end-to-end time from Artificial Analysis & other sources, snapshot 2026-10-25.

Trade-off

OpenAIGPT-6 Luna (High)On the frontier

Intelligence: 32.90
Total cost: $47.9

StepFunStep 5 PreviewOff the frontier

Intelligence: 43.70
Total cost: $1190

Verdict

Depends on your budget

Step 5 Preview scores 10.8 points higher (43.7 vs 32.9) but costs 25× as much to run the benchmark ($1190 vs $47.9; premium vs budget cost classes). They are not alternatives at one budget: pick Step 5 Preview when you need intelligence above 32.9, and GPT-6 Luna (High) when 32.9 is enough.

Metric	GPT-6 Luna (High)	Step 5 Preview	Difference
Intelligence (higher is better)	32.9	43.7	+32.8% Step 5 Preview is 32.8% more intelligent
Total AA cost (lower is better)	$47.85	$1,190.26	+2387.5% Step 5 Preview is 25× more expensive
End-to-end time (lower is better)	13.76s	12.08s	−12.2% Step 5 Preview is 12.2% faster
Price per 1M tokens (in / out)	$0.10 / $0.50	$1.00 / $2.70
Input modalities	Text, Image	Text, Image

Step 5 Preview vs GPT-6 Luna (High): 32.8% more intelligence, 2387.5% more cost to run the AA benchmark, and 12.2% faster end-to-end.

Open this matchup in the interactive picker GPT-6 Luna (High): what beats it Step 5 Preview: what beats it

Today's Pareto frontier

Against the frontier

GPT-6 Luna (High) is on today's frontier: nothing is both smarter and cheaper.
Step 5 Preview is off the frontier: at the same or lower cost, GPT-6.1 Sol (Max) scores 51.80 for $1082.

GPT-6 Luna (High)Step 5 PreviewToday's Pareto frontierOpen-weights frontierEvery other model

Matchup

Compare something else

Agents: Accept: text/markdown or ?format=md returns this page as Markdown. JSON: /api/v1/compare/gpt-6-luna-high/step-5 · Markdown: /api/v1/compare/gpt-6-luna-high/step-5?format=md · llms.txt · agent skill