Model comparison
GPT-5.6 Sol vs Step 5 Preview
GPT-5.6 Sol is the stronger model overall, scoring 65.0 to 47.9 on the Noometry Index. Step 5 Preview costs 5.6× less per token, which makes it the better buy when GPT-5.6 Sol's lead doesn't matter for your workload.
Last verified . 18 shared benchmarks.
StepFunSummary
- They share 18 benchmarks with published results for both. GPT-5.6 Sol scores higher in 9 categories and Step 5 Preview in 0 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in math, where GPT-5.6 Sol leads 85.6 to 46.1.
- The biggest single-benchmark swing is ProofBench: 83% for GPT-5.6 Sol and 42% for Step 5 Preview.
- Step 5 Preview is cheaper at $1 / $2.70 per million input/output tokens, against $4 / $20 for GPT-5.6 Sol.
- GPT-5.6 Sol accepts more context: 1.05M tokens versus 1.02M.
Side by side
| GPT-5.6 Sol | Step 5 Preview | |
|---|---|---|
| Provider | OpenAI | StepFun |
| Noometry Index | 65.0 | 47.9 |
| Released | 2026-07-09 | 2026-09-16 |
| Weights | Proprietary | Proprietary |
| Context window | 1.05M | 1.02M |
| Max output | 128K | 66K |
| Input $ / M tokens | $4 | $1 |
| Output $ / M tokens | $20 | $2.70 |
| Results tracked | 65 | 18 |
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Category by category
Coding GPT-5.6 Sol leads
GPT-5.6 Sol: 65.1 (#7), Step 5 Preview: 51.8 (#36)
| Benchmark | GPT-5.6 Sol | Step 5 Preview |
|---|---|---|
| LMArena WebDev | 1618 | 1564 |
| SciCode | 57.1% | 58.9% |
| LMArena Coding | 1498 | 1480 |
| DeepSWE | 72.7% | — |
| FrontierCode | 47.5% | — |
| CursorBench | 41.7% | — |
| FrontierSWE | 32.2% | — |
| GSO | 76.5% | — |
| WeirdML | 89.4% | — |
| MirrorCode | 20% | — |
| ALE-Bench | 2,177 | — |
Agentic & Tool Use Not comparable
GPT-5.6 Sol: 50.3 (#7), Step 5 Preview: —
| Benchmark | GPT-5.6 Sol | Step 5 Preview |
|---|---|---|
| APEX-Agents | 51.4% | — |
| OSWorld 2.0 | 27.3% | — |
| τ²-bench Banking | 46.9% | — |
| PostTrainBench | 36.2% | — |
| BALROG | 60% | — |
| GBAEval | 52.6% | — |
| GDP.pdf | 30.7% | — |
| LMArena Search | 1257 | — |
| Vending-Bench 2 | 9,619 | — |
Reasoning GPT-5.6 Sol leads
GPT-5.6 Sol: 74.8 (#8), Step 5 Preview: 40.0 (#57)
| Benchmark | GPT-5.6 Sol | Step 5 Preview |
|---|---|---|
| CritPt | 32.3% | 20.9% |
| LMArena Hard Prompts | 1484 | 1465 |
| ARC-AGI-2 | 92.5% | — |
| SimpleBench | 71.7% | — |
| Kagi LLM Benchmark | 67% | — |
| NYT Connections (extended) | 93.8% | — |
| ARC-AGI-1 | 97.5% | — |
| Chess Puzzles | 64% | — |
| EnigmaEval | 37.1% | — |
| EBR-Bench | 44.8% | — |
| Mystery Game Puzzles | 58% | — |
| DTBench | 96% | — |
| LMCA | 59.2% | — |
| Surface Evolver Bench | 93.1% | — |
| Bench to the Future 3 | 0.14 | — |
| Epoch Capabilities Index | 161.66 | — |
Math GPT-5.6 Sol leads
GPT-5.6 Sol: 85.6 (#9), Step 5 Preview: 46.1 (#72)
| Benchmark | GPT-5.6 Sol | Step 5 Preview |
|---|---|---|
| ProofBench | 83% | 42% |
| LMArena Math | 1474 | 1470 |
| FrontierMath (Tiers 1-3) | 89.1% | — |
| FrontierMath Tier 4 | 82.9% | — |
| OTIS Mock AIME 2024-2025 | 100% | — |
| FrontierMath Erdős | 0% | — |
Knowledge GPT-5.6 Sol leads
GPT-5.6 Sol: 64.3 (#18), Step 5 Preview: 41.2 (#112)
| Benchmark | GPT-5.6 Sol | Step 5 Preview |
|---|---|---|
| LMArena Expert | 1516 | 1470 |
| GPQA Diamond | 93.5% | — |
| SimpleQA Verified | 69.7% | — |
| Vectara Hallucination Rate | 12.4% | — |
Multimodal GPT-5.6 Sol leads
GPT-5.6 Sol: 48.6 (#9), Step 5 Preview: 41.0 (#41)
| Benchmark | GPT-5.6 Sol | Step 5 Preview |
|---|---|---|
| LMArena Vision | 1281 | 1267 |
| Blueprint-Bench 2 | 33.6% | — |
| Furniture Assembly | 56.7% | — |
| LMArena Document | 1483 | — |
Multilingual GPT-5.6 Sol leads
GPT-5.6 Sol: 55.3 (#32), Step 5 Preview: 53.8 (#54)
| Benchmark | GPT-5.6 Sol | Step 5 Preview |
|---|---|---|
| LMArena Non-English | 1452 | 1432 |
| LMArena Chinese | 1527 | 1519 |
| LMArena Russian | 1468 | 1436 |
| LMArena Spanish | 1441 | 1439 |
| LMArena French | 1477 | — |
| LMArena German | 1476 | — |
| LMArena Japanese | 1471 | — |
| LMArena Korean | 1442 | — |
Instruction Following GPT-5.6 Sol leads
GPT-5.6 Sol: 77.7 (#16), Step 5 Preview: 76.0 (#50)
| Benchmark | GPT-5.6 Sol | Step 5 Preview |
|---|---|---|
| LMArena Instruction Following | 1482 | 1444 |
Long Context Too close to call
GPT-5.6 Sol: 45.4 (#42), Step 5 Preview: 44.5 (#64)
| Benchmark | GPT-5.6 Sol | Step 5 Preview |
|---|---|---|
| LMArena Longer Query | 1480 | 1455 |
Writing & Preference GPT-5.6 Sol leads
GPT-5.6 Sol: 73.3 (#12), Step 5 Preview: 62.8 (#71)
| Benchmark | GPT-5.6 Sol | Step 5 Preview |
|---|---|---|
| LMArena Text | 1457 | 1442 |
| LMArena Creative Writing | 1448 | 1410 |
| LMArena Multi-Turn | 1460 | 1447 |
| EQ-Bench Creative Writing | 1972 | — |
| EQ-Bench 4 | 1250 | — |
Frequently asked questions
Is GPT-5.6 Sol better than Step 5 Preview?
GPT-5.6 Sol is the stronger model overall, scoring 65.0 to 47.9 on the Noometry Index. Step 5 Preview costs 5.6× less per token, which makes it the better buy when GPT-5.6 Sol's lead doesn't matter for your workload.
Which is cheaper, GPT-5.6 Sol or Step 5 Preview?
Step 5 Preview is cheaper. It lists at $1 per million input tokens and $2.70 per million output tokens; GPT-5.6 Sol lists at $4 and $20.
Is GPT-5.6 Sol or Step 5 Preview better for coding?
GPT-5.6 Sol scores higher on coding benchmarks: 65.1 versus 51.8 in the Noometry coding category.
Which has the bigger context window?
GPT-5.6 Sol does, with 1.05M tokens against 1.02M.
How many benchmarks do GPT-5.6 Sol and Step 5 Preview share?
18 benchmarks have published results for both models. GPT-5.6 Sol has 65 scored results on Noometry and Step 5 Preview has 18.