Model comparison

GPT-4.5 vs GPT-5.6 Sol

GPT-5.6 Sol is the stronger model overall, scoring 65.0 to 37.2 on the Noometry Index.

Last verified . 26 shared benchmarks.

GPT-4.5 OpenAI

37.2

Rank #208 Confirmed

GPT-5.6 Sol OpenAI

65.0

Rank #7 Confirmed

Summary

  • They share 26 benchmarks with published results for both. GPT-4.5 scores higher in 0 categories and GPT-5.6 Sol in 10 categories; 10 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where GPT-5.6 Sol leads 74.8 to 13.9.
  • The biggest single-benchmark swing is ARC-AGI-2: 0.8% for GPT-4.5 and 92.5% for GPT-5.6 Sol.

Side by side

GPT-4.5 and GPT-5.6 Sol specifications
GPT-4.5GPT-5.6 Sol
ProviderOpenAIOpenAI
Noometry Index37.265.0
Released2025-02-272026-07-09
WeightsProprietaryProprietary
Context window—1.05M
Max output—128K
Input $ / M tokens—$4
Output $ / M tokens—$20
Results tracked4265

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Category by category

Coding GPT-5.6 Sol leads

GPT-4.5: 42.2 (#109), GPT-5.6 Sol: 65.1 (#7)

Coding benchmarks
BenchmarkGPT-4.5GPT-5.6 Sol
WeirdML39.4%89.4%
LMArena Coding13961498
DeepSWE—72.7%
FrontierCode—47.5%
Aider Polyglot44.9%—
CursorBench—41.7%
LMArena WebDev—1618
FrontierSWE—32.2%
SciCode—57.1%
GSO—76.5%
LiveBench Coding75.2%—
MirrorCode—20%
ALE-Bench—2,177

Agentic & Tool Use GPT-5.6 Sol leads

GPT-4.5: 27.9 (#97), GPT-5.6 Sol: 50.3 (#7)

Agentic & Tool Use benchmarks
BenchmarkGPT-4.5GPT-5.6 Sol
APEX-Agents—51.4%
OSWorld 2.0—27.3%
τ²-bench Banking—46.9%
Cybench17.5%—
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-4.5: 13.9 (#330), GPT-5.6 Sol: 74.8 (#8)

Reasoning benchmarks
BenchmarkGPT-4.5GPT-5.6 Sol
ARC-AGI-20.8%92.5%
SimpleBench34.5%71.7%
ARC-AGI-110.3%97.5%
EnigmaEval3.2%37.1%
LMArena Hard Prompts14031484
Epoch Capabilities Index136.74161.66
Kagi LLM Benchmark—67%
NYT Connections (extended)—93.8%
CritPt—32.3%
Chess Puzzles—64%
EBR-Bench—44.8%
LiveBench Reasoning71.1%—
Mystery Game Puzzles—58%
DTBench—96%
LiveBench Data Analysis64.3%—
LMCA—59.2%
Surface Evolver Bench—93.1%
Bench to the Future 3—0.14
ForecastBench61.7—
LiveBench69%—

Math GPT-5.6 Sol leads

GPT-4.5: 32.6 (#211), GPT-5.6 Sol: 85.6 (#9)

Math benchmarks
BenchmarkGPT-4.5GPT-5.6 Sol
OTIS Mock AIME 2024-202537.8%100%
LMArena Math14121474
FrontierMath (Tiers 1-3)—89.1%
FrontierMath Tier 4—82.9%
ProofBench—83%
LiveBench Math69.3%—
MATH Level 578.6%—
FrontierMath Erdős—0%

Knowledge GPT-5.6 Sol leads

GPT-4.5: 32.5 (#211), GPT-5.6 Sol: 64.3 (#18)

Knowledge benchmarks
BenchmarkGPT-4.5GPT-5.6 Sol
GPQA Diamond68.7%93.5%
LMArena Expert13941516
Humanity's Last Exam5.4%—
SimpleQA Verified—69.7%
Confabulations13.6%—
Vectara Hallucination Rate—12.4%

Multimodal GPT-5.6 Sol leads

GPT-4.5: 37.6 (#71), GPT-5.6 Sol: 48.6 (#9)

Multimodal benchmarks
BenchmarkGPT-4.5GPT-5.6 Sol
LMArena Vision11951281
VPCT45%—
Blueprint-Bench 2—33.6%
Furniture Assembly—56.7%
LMArena Document—1483

Multilingual GPT-5.6 Sol leads

GPT-4.5: 52.5 (#83), GPT-5.6 Sol: 55.3 (#32)

Multilingual benchmarks
BenchmarkGPT-4.5GPT-5.6 Sol
LMArena Non-English14131452
LMArena Chinese14211527
LMArena French14181477
LMArena German14571476
LMArena Japanese14161471
LMArena Korean13921442
LMArena Russian14191468
LMArena Spanish—1441

Instruction Following GPT-5.6 Sol leads

GPT-4.5: 72.6 (#134), GPT-5.6 Sol: 77.7 (#16)

Instruction Following benchmarks
BenchmarkGPT-4.5GPT-5.6 Sol
LMArena Instruction Following14041482
LiveBench Instruction Following72.3%—

Long Context GPT-5.6 Sol leads

GPT-4.5: 40.4 (#155), GPT-5.6 Sol: 45.4 (#42)

Long Context benchmarks
BenchmarkGPT-4.5GPT-5.6 Sol
LMArena Longer Query14061480
Fiction.LiveBench63.9%—

Writing & Preference GPT-5.6 Sol leads

GPT-4.5: 56.9 (#134), GPT-5.6 Sol: 73.3 (#12)

Writing & Preference benchmarks
BenchmarkGPT-4.5GPT-5.6 Sol
LMArena Text14171457
LMArena Creative Writing13941448
EQ-Bench Creative Writing12581972
LMArena Multi-Turn14441460
Short-Story Creative Writing75.6%—
EQ-Bench 4—1250
LiveBench Language61.5%—

Frequently asked questions

Is GPT-4.5 better than GPT-5.6 Sol?

GPT-5.6 Sol is the stronger model overall, scoring 65.0 to 37.2 on the Noometry Index.

Is GPT-4.5 or GPT-5.6 Sol better for coding?

GPT-5.6 Sol scores higher on coding benchmarks: 65.1 versus 42.2 in the Noometry coding category.

How many benchmarks do GPT-4.5 and GPT-5.6 Sol share?

26 benchmarks have published results for both models. GPT-4.5 has 42 scored results on Noometry and GPT-5.6 Sol has 65.

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