Noometry

Model comparison

GPT-5.5 Instant vs Grok 3

GPT-5.5 Instant is the stronger model overall, scoring 42.5 to 39.6 on the Noometry Index.

Last verified . 20 shared benchmarks.

GPT-5.5 Instant OpenAI

42.5

Rank #99 Confirmed

Grok 3 xAI

39.6

Rank #150 Confirmed

Summary

  • They share 20 benchmarks with published results for both. GPT-5.5 Instant scores higher in 6 categories and Grok 3 in 2 categories; 6 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where GPT-5.5 Instant leads 24.2 to 13.8.
  • The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 68.1% for GPT-5.5 Instant and 55.6% for Grok 3.

Side by side

GPT-5.5 InstantGrok 3
ProviderOpenAIxAI
Noometry Index42.539.6
Released2026-05-052025-04-09
WeightsProprietaryProprietary
Context window——
Max output——
Input $ / M tokens——
Output $ / M tokens——
Results tracked2740

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Category by category

Coding GPT-5.5 Instant leads

GPT-5.5 Instant: 43.7 (#73), Grok 3: 41.5 (#113)

BenchmarkGPT-5.5 InstantGrok 3
LMArena Coding14331432
Aider Polyglot—53.3%
SciCode48.6%—
WeirdML—37.2%

Agentic & Tool Use Not comparable

GPT-5.5 Instant: —, Grok 3: 30.2 (#69)

BenchmarkGPT-5.5 InstantGrok 3
BALROG—29.5%

Reasoning GPT-5.5 Instant leads

GPT-5.5 Instant: 24.2 (#149), Grok 3: 13.8 (#322)

BenchmarkGPT-5.5 InstantGrok 3
LMArena Hard Prompts14261433
Epoch Capabilities Index142.48138.34
ARC-AGI-2—0%
SimpleBench—36.1%
Kagi LLM Benchmark—61.3%
ARC-AGI-1—5.5%
CritPt0%—
Chess Puzzles12%—

Math Grok 3 leads

GPT-5.5 Instant: 26.1 (#241), Grok 3: 36.2 (#122)

BenchmarkGPT-5.5 InstantGrok 3
OTIS Mock AIME 2024-202568.1%55.6%
LMArena Math14201390
FrontierMath (Tiers 1-3)26.3%—
FrontierMath Tier 42.4%—
Omni-MATH—46.4%
MATH Level 5—88.7%
FrontierMath (Feb 2025 set)—3.8%
FrontierMath Tier 4 (v1)—0%

Knowledge GPT-5.5 Instant leads

GPT-5.5 Instant: 48.9 (#68), Grok 3: 46.0 (#76)

BenchmarkGPT-5.5 InstantGrok 3
GPQA Diamond82.5%75.8%
LMArena Expert14091420
MMLU-Pro—78.8%
Confabulations—14.2%
Vectara Hallucination Rate—5.8%
GPQA (HELM)—65%

Multimodal Not comparable

GPT-5.5 Instant: 39.3 (#48), Grok 3: —

BenchmarkGPT-5.5 InstantGrok 3
LMArena Vision1250—
LMArena Document1403—

Multilingual Too close to call

GPT-5.5 Instant: 53.0 (#76), Grok 3: 52.5 (#81)

BenchmarkGPT-5.5 InstantGrok 3
LMArena Non-English14171411
LMArena Chinese14571448
LMArena French14281460
LMArena German14101431
LMArena Japanese14081389
LMArena Korean13931374
LMArena Russian14301416
LMArena Spanish14301417

Instruction Following Too close to call

GPT-5.5 Instant: 74.4 (#94), Grok 3: 75.2 (#69)

BenchmarkGPT-5.5 InstantGrok 3
LMArena Instruction Following14071409
IFEval—88.4%

Long Context GPT-5.5 Instant leads

GPT-5.5 Instant: 43.4 (#92), Grok 3: 38.7 (#187)

BenchmarkGPT-5.5 InstantGrok 3
LMArena Longer Query14221439
Fiction.LiveBench—58.3%

Writing & Preference GPT-5.5 Instant leads

GPT-5.5 Instant: 62.0 (#81), Grok 3: 56.0 (#136)

BenchmarkGPT-5.5 InstantGrok 3
LMArena Text14191426
LMArena Creative Writing14201414
LMArena Multi-Turn14341424
Short-Story Creative Writing—76.4%
EQ-Bench Creative Writing—1186
WildBench—84.9%

Frequently asked questions

Is GPT-5.5 Instant better than Grok 3?

GPT-5.5 Instant is the stronger model overall, scoring 42.5 to 39.6 on the Noometry Index.

Is GPT-5.5 Instant or Grok 3 better for coding?

GPT-5.5 Instant scores higher on coding benchmarks: 43.7 versus 41.5 in the Noometry coding category.

How many benchmarks do GPT-5.5 Instant and Grok 3 share?

20 benchmarks have published results for both models. GPT-5.5 Instant has 27 scored results on Noometry and Grok 3 has 40.

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