Head-to-head AI model comparison graphic: GPT-5.6 Luna (OpenAI) vs Step 5 Preview (StepFun). Intelligence index 23.8 vs 28.5; output speed 125 vs 151 tokens per second; time to first token 108s vs 0.91s; output price $1.20 vs $2.70 per million tokens; input price $0.20 vs $1.00 per million tokens. franklineh.com
GPT-5.6 Luna vs Step 5 Preview: head-to-head AI benchmark comparison. Step 5 Preview leads on intelligence index, output speed and time to first token; GPT-5.6 Luna leads on output price and input price.
Head to headBy Franklin AIUpdated

GPT-5.6 Luna Max vs Step 5 Preview compared

Step 5 Preview leads the intelligence index 28.5 to 23.8. GPT-5.6 Luna Max costs 68% less on blended price. Compare price, speed, latency and a clear verdict.

Pick it for GPT-5.6 Luna · Max

  • Lower cost: $0.44 against $1.54 for 1 million input and 200,000 output tokens.

Pick it for Step 5 Preview

  • Shorter wait for the first token: 0.91 seconds against 108 seconds.
  • Higher intelligence index: 28.5 against 23.8.
  • Faster output: 151 tokens per second against 125 tokens per second.

By the numbers

MetricGPT-5.6 Luna (Max)Step 5 Preview
Intelligence Index23.828.5
Input price (per 1M tokens)$0.20$1.00
Output price (per 1M tokens)$1.20$2.70
Output speed (tokens/s)125151
Time to first token108s0.91s
Release date2026-07-092026-09-18

This comparison puts OpenAI's GPT-5.6 Luna (Max) next to StepFun's Step 5 Preview. Time to first token is the standout number here: 0.91 seconds for Step 5 Preview, 108 seconds for GPT-5.6 Luna Max. Everything below is read from the benchmark, price and speed data in Franklin AI's catalogue; nothing here comes from a hands-on test.

Step 5 Preview is the faster writer

Once a response is under way, GPT-5.6 Luna Max produces roughly 125 tokens per second against 151 tokens per second for Step 5 Preview. On long outputs, that is a real advantage for Step 5 Preview. Time to first token is 108 seconds for GPT-5.6 Luna Max and 0.91 seconds for Step 5 Preview. In an interactive app, Step 5 Preview will feel noticeably more responsive. Waits that long are felt on every chat-style request, though they matter less for batch jobs.

Put together, a 400-token answer would take about 111 seconds from GPT-5.6 Luna Max and 3.6 seconds from Step 5 Preview, counting the first-token wait.

The headline benchmark

The catalogue puts GPT-5.6 Luna Max at 23.8 and Step 5 Preview at 28.5 on its intelligence index. A lead of this size is hard to dismiss as noise. In relative terms, Step 5 Preview scores 20% higher.

Among 109 active scored models, GPT-5.6 Luna Max sits 70th and Step 5 Preview 61st.

Specialist coding and math indexes are missing for both, so treat the overall score as the only capability signal here.

Generation gap

Step 5 Preview arrived on September 18, 2026, about 2 months after GPT-5.6 Luna Max (July 9, 2026).

Cost: GPT-5.6 Luna Max is cheaper

GPT-5.6 Luna Max lists $0.20 per million input tokens and $1.20 per million output tokens; Step 5 Preview lists $1.00 and $2.70. That makes GPT-5.6 Luna Max's output 56% cheaper.

Take 1 million input tokens and 200,000 output tokens: that comes to $0.44 on GPT-5.6 Luna Max and $1.54 on Step 5 Preview. A bigger example, summarising 1,000 documents of 8,000 tokens into 400-token summaries, costs $2.08 on GPT-5.6 Luna Max and $9.08 on Step 5 Preview: a gap of $7.00. On a 3:1 blend of input to output tokens, that works out to $0.45 versus $1.425 per million.

Cost per point of intelligence

Dividing the blended price by the intelligence index gives a rough cost per point: $0.019 for GPT-5.6 Luna Max and $0.050 for Step 5 Preview, per million tokens. Step 5 Preview costs 2.6 times as much per point, which is the price of its lead.

Frequently asked questions

Is GPT-5.6 Luna Max better than Step 5 Preview?

It depends on what you need: Step 5 Preview scores higher on the intelligence index, 28.5 to 23.8; GPT-5.6 Luna Max is 68% cheaper on blended price; and Step 5 Preview streams output 1.2 times as fast.

Which model has lower latency?

Step 5 Preview generates output faster, at 151 tokens per second against 125 tokens per second. Step 5 Preview reaches its first token sooner (0.91 seconds against 108 seconds).

Which is newer, GPT-5.6 Luna Max or Step 5 Preview?

Step 5 Preview is newer. It was released on September 18, 2026, about 2 months after GPT-5.6 Luna Max (July 9, 2026).

Was this comparison tested by hand?

The figures are the recorded benchmark, price and speed data in Franklin AI's model catalogue. This page is written from that data automatically; neither model was tested by hand for it.

Who makes GPT-5.6 Luna Max and Step 5 Preview?

GPT-5.6 Luna Max is made by OpenAI and Step 5 Preview by StepFun. GPT-5.6 Luna Max was released on July 9, 2026 and Step 5 Preview on September 18, 2026.

Final whistle

Step 5 Preview has more going for it here, but GPT-5.6 Luna Max is not without an argument. Pick GPT-5.6 Luna Max if cost matters ($1.20 against $2.70 per million output tokens). Pick Step 5 Preview if users are waiting on the first word and you need the higher overall score (28.5 against 23.8).

Where the numbers come from

The scores, speed and prices in this comparison come from independent third-party model evaluations that Franklin AI syncs each day, and the article was written from a snapshot of them. For the latest results, open the GPT-5.6 Luna (Max) and Step 5 Preview pages. The AI Benchmark methodology explains how that data is collected and shown.

Comments (0)

No comments yet

Be the first to share your thoughts!