Noometry

Model comparison

GPT-4.5 vs Grok 4 Fast

Grok 4 Fast is the stronger model overall, scoring 39.4 to 37.2 on the Noometry Index.

Last verified . 23 shared benchmarks.

GPT-4.5 OpenAI

37.2

Rank #208 Confirmed

Grok 4 Fast xAI

39.4

Rank #167 Confirmed

Summary

  • They share 23 benchmarks with published results for both. GPT-4.5 scores higher in 3 categories and Grok 4 Fast in 6 categories; 7 gaps are clear of the uncertainty.
  • The widest gap is in long context, where Grok 4 Fast leads 63.2 to 40.4.
  • The biggest single-benchmark swing is ARC-AGI-1: 10.3% for GPT-4.5 and 48.5% for Grok 4 Fast.

Side by side

GPT-4.5Grok 4 Fast
ProviderOpenAIxAI
Noometry Index37.239.4
Released2025-02-272025-09-19
WeightsProprietaryProprietary
Context window——
Max output——
Input $ / M tokens——
Output $ / M tokens——
Results tracked4230

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Category by category

Coding GPT-4.5 leads

GPT-4.5: 42.2 (#109), Grok 4 Fast: 32.5 (#271)

BenchmarkGPT-4.5Grok 4 Fast
WeirdML39.4%42.9%
LMArena Coding13961429
Aider Polyglot44.9%—
LMArena WebDev—1159
LiveBench Coding75.2%—

Agentic & Tool Use Grok 4 Fast leads

GPT-4.5: 27.9 (#97), Grok 4 Fast: 29.5 (#86)

BenchmarkGPT-4.5Grok 4 Fast
Cybench17.5%30%
τ²-bench Banking—15.7%
LMArena Search—1171

Reasoning Grok 4 Fast leads

GPT-4.5: 13.9 (#330), Grok 4 Fast: 22.2 (#201)

BenchmarkGPT-4.5Grok 4 Fast
ARC-AGI-20.8%5.3%
ARC-AGI-110.3%48.5%
LMArena Hard Prompts14031412
Epoch Capabilities Index136.74144.2
ForecastBench61.760.5
SimpleBench34.5%—
Kagi LLM Benchmark—66.1%
EnigmaEval3.2%—
LiveBench Reasoning71.1%—
DTBench—82.7%
LiveBench Data Analysis64.3%—
LiveBench69%—

Math Grok 4 Fast leads

GPT-4.5: 32.6 (#211), Grok 4 Fast: 38.9 (#123)

BenchmarkGPT-4.5Grok 4 Fast
LMArena Math14121419
OTIS Mock AIME 2024-202537.8%—
LiveBench Math69.3%—
MATH Level 578.6%—

Knowledge Too close to call

GPT-4.5: 32.5 (#211), Grok 4 Fast: 32.0 (#214)

BenchmarkGPT-4.5Grok 4 Fast
LMArena Expert13941411
GPQA Diamond68.7%—
Humanity's Last Exam5.4%—
Confabulations13.6%—
Vectara Hallucination Rate—19.7%

Multimodal Not comparable

GPT-4.5: 37.6 (#71), Grok 4 Fast: —

BenchmarkGPT-4.5Grok 4 Fast
LMArena Vision1195—
VPCT45%—

Multilingual GPT-4.5 leads

GPT-4.5: 52.5 (#83), Grok 4 Fast: 51.3 (#111)

BenchmarkGPT-4.5Grok 4 Fast
LMArena Non-English14131396
LMArena Chinese14211457
LMArena French14181431
LMArena German14571383
LMArena Japanese14161352
LMArena Korean13921357
LMArena Russian14191389
LMArena Spanish—1415

Instruction Following Too close to call

GPT-4.5: 72.6 (#134), Grok 4 Fast: 73.2 (#121)

BenchmarkGPT-4.5Grok 4 Fast
LMArena Instruction Following14041387
LiveBench Instruction Following72.3%—

Long Context Grok 4 Fast leads

GPT-4.5: 40.4 (#155), Grok 4 Fast: 63.2 (#3)

BenchmarkGPT-4.5Grok 4 Fast
Fiction.LiveBench63.9%94.4%
LMArena Longer Query14061415

Writing & Preference Grok 4 Fast leads

GPT-4.5: 56.9 (#134), Grok 4 Fast: 60.0 (#102)

BenchmarkGPT-4.5Grok 4 Fast
LMArena Text14171407
LMArena Creative Writing13941387
LMArena Multi-Turn14441414
Short-Story Creative Writing75.6%—
EQ-Bench Creative Writing1258—
LiveBench Language61.5%—

Frequently asked questions

Is GPT-4.5 better than Grok 4 Fast?

Grok 4 Fast is the stronger model overall, scoring 39.4 to 37.2 on the Noometry Index.

Is GPT-4.5 or Grok 4 Fast better for coding?

GPT-4.5 scores higher on coding benchmarks: 42.2 versus 32.5 in the Noometry coding category.

How many benchmarks do GPT-4.5 and Grok 4 Fast share?

23 benchmarks have published results for both models. GPT-4.5 has 42 scored results on Noometry and Grok 4 Fast has 30.

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