Noometry

Model comparison

GPT-4.5 vs GPT-5.5 Instant

GPT-5.5 Instant is the stronger model overall, scoring 42.5 to 36.9 on the Noometry Index.

Last verified . 20 shared benchmarks.

GPT-4.5 OpenAI

36.9

Rank #200 Confirmed

GPT-5.5 Instant OpenAI

42.5

Rank #99 Confirmed

Summary

  • They share 20 benchmarks with published results for both. GPT-4.5 scores higher in 1 category and GPT-5.5 Instant in 8 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in knowledge, where GPT-5.5 Instant leads 48.9 to 32.4.
  • The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 37.8% for GPT-4.5 and 68.1% for GPT-5.5 Instant.

Side by side

GPT-4.5GPT-5.5 Instant
ProviderOpenAIOpenAI
Noometry Index36.942.5
Released2025-02-272026-05-05
WeightsProprietaryProprietary
Context window——
Max output——
Input $ / M tokens——
Output $ / M tokens——
Results tracked4227

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Category by category

Coding GPT-5.5 Instant leads

GPT-4.5: 41.8 (#102), GPT-5.5 Instant: 43.7 (#73)

BenchmarkGPT-4.5GPT-5.5 Instant
LMArena Coding13971433
Aider Polyglot44.9%—
SciCode—48.6%
WeirdML39.4%—
LiveBench Coding75.2%—

Agentic & Tool Use Not comparable

GPT-4.5: 27.6 (#92), GPT-5.5 Instant: —

BenchmarkGPT-4.5GPT-5.5 Instant
Cybench17.5%—

Reasoning GPT-5.5 Instant leads

GPT-4.5: 14.1 (#320), GPT-5.5 Instant: 24.2 (#149)

BenchmarkGPT-4.5GPT-5.5 Instant
LMArena Hard Prompts14041426
Epoch Capabilities Index136.74142.48
ARC-AGI-20.8%—
SimpleBench34.5%—
ARC-AGI-110.3%—
CritPt—0%
Chess Puzzles—12%
EnigmaEval3.2%—
LiveBench Reasoning71.1%—
LiveBench Data Analysis64.3%—
ForecastBench61.7—
LiveBench69%—

Math GPT-4.5 leads

GPT-4.5: 31.0 (#200), GPT-5.5 Instant: 26.1 (#241)

BenchmarkGPT-4.5GPT-5.5 Instant
OTIS Mock AIME 2024-202537.8%68.1%
LMArena Math14121420
FrontierMath (Tiers 1-3)—26.3%
FrontierMath Tier 4—2.4%
LiveBench Math69.3%—
MATH Level 578.6%—

Knowledge GPT-5.5 Instant leads

GPT-4.5: 32.4 (#205), GPT-5.5 Instant: 48.9 (#68)

BenchmarkGPT-4.5GPT-5.5 Instant
GPQA Diamond68.7%82.5%
LMArena Expert13941409
Humanity's Last Exam5.4%—
Confabulations13.6%—

Multimodal GPT-5.5 Instant leads

GPT-4.5: 37.0 (#68), GPT-5.5 Instant: 39.3 (#48)

BenchmarkGPT-4.5GPT-5.5 Instant
LMArena Vision11951250
VPCT45%—
LMArena Document—1403

Multilingual Too close to call

GPT-4.5: 52.7 (#78), GPT-5.5 Instant: 53.0 (#76)

BenchmarkGPT-4.5GPT-5.5 Instant
LMArena Non-English14131417
LMArena Chinese14211457
LMArena French14171428
LMArena German14571410
LMArena Japanese14161408
LMArena Korean13921393
LMArena Russian14191430
LMArena Spanish—1430

Instruction Following GPT-5.5 Instant leads

GPT-4.5: 72.8 (#129), GPT-5.5 Instant: 74.4 (#94)

BenchmarkGPT-4.5GPT-5.5 Instant
LMArena Instruction Following14041407
LiveBench Instruction Following72.3%—

Long Context GPT-5.5 Instant leads

GPT-4.5: 40.4 (#150), GPT-5.5 Instant: 43.4 (#92)

BenchmarkGPT-4.5GPT-5.5 Instant
LMArena Longer Query14061422
Fiction.LiveBench63.9%—

Writing & Preference GPT-5.5 Instant leads

GPT-4.5: 57.1 (#129), GPT-5.5 Instant: 62.0 (#81)

BenchmarkGPT-4.5GPT-5.5 Instant
LMArena Text14171419
LMArena Creative Writing13941420
LMArena Multi-Turn14441434
Short-Story Creative Writing75.6%—
EQ-Bench Creative Writing1258—
LiveBench Language61.5%—

Frequently asked questions

Is GPT-4.5 better than GPT-5.5 Instant?

GPT-5.5 Instant is the stronger model overall, scoring 42.5 to 36.9 on the Noometry Index.

Is GPT-4.5 or GPT-5.5 Instant better for coding?

GPT-5.5 Instant scores higher on coding benchmarks: 43.7 versus 41.8 in the Noometry coding category.

How many benchmarks do GPT-4.5 and GPT-5.5 Instant share?

20 benchmarks have published results for both models. GPT-4.5 has 42 scored results on Noometry and GPT-5.5 Instant has 27.

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