Model comparison

GPT-5.6 Sol vs Step 3

GPT-5.6 Sol is the stronger model overall, scoring 65.0 to 40.5 on the Noometry Index.

Last verified . 17 shared benchmarks.

GPT-5.6 Sol OpenAI

65.0

Rank #7 Confirmed

Step 3 StepFun

40.5

Rank #149 Confirmed

Summary

  • They share 17 benchmarks with published results for both. GPT-5.6 Sol scores higher in 9 categories and Step 3 in 0 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in math, where GPT-5.6 Sol leads 85.6 to 37.6.
  • Step 3 has downloadable open weights; the other is API-only.

Side by side

GPT-5.6 Sol and Step 3 specifications
GPT-5.6 SolStep 3
ProviderOpenAIStepFun
Noometry Index65.040.5
Released2026-07-09—
WeightsProprietaryOpen
Context window1.05M—
Max output128K—
Input $ / M tokens$4—
Output $ / M tokens$20—
Results tracked6517

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Category by category

Coding GPT-5.6 Sol leads

GPT-5.6 Sol: 65.1 (#7), Step 3: 40.1 (#147)

Coding benchmarks
BenchmarkGPT-5.6 SolStep 3
LMArena Coding14981367
DeepSWE72.7%—
FrontierCode47.5%—
CursorBench41.7%—
LMArena WebDev1618—
FrontierSWE32.2%—
SciCode57.1%—
GSO76.5%—
WeirdML89.4%—
MirrorCode20%—
ALE-Bench2,177—

Agentic & Tool Use Not comparable

GPT-5.6 Sol: 50.3 (#7), Step 3: —

Agentic & Tool Use benchmarks
BenchmarkGPT-5.6 SolStep 3
APEX-Agents51.4%—
OSWorld 2.027.3%—
τ²-bench Banking46.9%—
PostTrainBench36.2%—
BALROG60%—
GBAEval52.6%—
GDP.pdf30.7%—
LMArena Search1257—
Vending-Bench 29,619—

Reasoning GPT-5.6 Sol leads

GPT-5.6 Sol: 74.8 (#8), Step 3: 28.4 (#105)

Reasoning benchmarks
BenchmarkGPT-5.6 SolStep 3
Kagi LLM Benchmark67%62.3%
LMArena Hard Prompts14841355
ARC-AGI-292.5%—
SimpleBench71.7%—
NYT Connections (extended)93.8%—
ARC-AGI-197.5%—
CritPt32.3%—
Chess Puzzles64%—
EnigmaEval37.1%—
EBR-Bench44.8%—
Mystery Game Puzzles58%—
DTBench96%—
LMCA59.2%—
Surface Evolver Bench93.1%—
Bench to the Future 30.14—
Epoch Capabilities Index161.66—

Math GPT-5.6 Sol leads

GPT-5.6 Sol: 85.6 (#9), Step 3: 37.6 (#148)

Math benchmarks
BenchmarkGPT-5.6 SolStep 3
LMArena Math14741366
FrontierMath (Tiers 1-3)89.1%—
FrontierMath Tier 482.9%—
OTIS Mock AIME 2024-2025100%—
ProofBench83%—
FrontierMath Erdős0%—

Knowledge GPT-5.6 Sol leads

GPT-5.6 Sol: 64.3 (#18), Step 3: 36.8 (#164)

Knowledge benchmarks
BenchmarkGPT-5.6 SolStep 3
LMArena Expert15161333
GPQA Diamond93.5%—
SimpleQA Verified69.7%—
Vectara Hallucination Rate12.4%—

Multimodal GPT-5.6 Sol leads

GPT-5.6 Sol: 48.6 (#9), Step 3: 35.5 (#86)

Multimodal benchmarks
BenchmarkGPT-5.6 SolStep 3
LMArena Vision12811177
Blueprint-Bench 233.6%—
Furniture Assembly56.7%—
LMArena Document1483—

Multilingual GPT-5.6 Sol leads

GPT-5.6 Sol: 55.3 (#32), Step 3: 46.3 (#159)

Multilingual benchmarks
BenchmarkGPT-5.6 SolStep 3
LMArena Non-English14521327
LMArena Chinese15271397
LMArena German14761371
LMArena Korean14421269
LMArena Russian14681331
LMArena Spanish14411371
LMArena French1477—
LMArena Japanese1471—

Instruction Following GPT-5.6 Sol leads

GPT-5.6 Sol: 77.7 (#16), Step 3: 70.4 (#164)

Instruction Following benchmarks
BenchmarkGPT-5.6 SolStep 3
LMArena Instruction Following14821332

Long Context GPT-5.6 Sol leads

GPT-5.6 Sol: 45.4 (#42), Step 3: 40.3 (#157)

Long Context benchmarks
BenchmarkGPT-5.6 SolStep 3
LMArena Longer Query14801326

Writing & Preference GPT-5.6 Sol leads

GPT-5.6 Sol: 73.3 (#12), Step 3: 54.3 (#151)

Writing & Preference benchmarks
BenchmarkGPT-5.6 SolStep 3
LMArena Text14571350
LMArena Creative Writing14481321
LMArena Multi-Turn14601341
EQ-Bench Creative Writing1972—
EQ-Bench 41250—

Frequently asked questions

Is GPT-5.6 Sol better than Step 3?

GPT-5.6 Sol is the stronger model overall, scoring 65.0 to 40.5 on the Noometry Index.

Is GPT-5.6 Sol or Step 3 better for coding?

GPT-5.6 Sol scores higher on coding benchmarks: 65.1 versus 40.1 in the Noometry coding category.

How many benchmarks do GPT-5.6 Sol and Step 3 share?

17 benchmarks have published results for both models. GPT-5.6 Sol has 65 scored results on Noometry and Step 3 has 17.

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