Noometry

Model comparison

GLM-5.1 vs Grok 4 Fast

GLM-5.1 is the stronger model overall, scoring 47.8 to 39.4 on the Noometry Index.

Last verified . 20 shared benchmarks.

GLM-5.1 Z.ai (Zhipu)

47.8

Rank #59 Confirmed

Grok 4 Fast xAI

39.4

Rank #167 Confirmed

Summary

  • They share 20 benchmarks with published results for both. GLM-5.1 scores higher in 7 categories and Grok 4 Fast in 2 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in knowledge, where GLM-5.1 leads 54.9 to 32.0.
  • The biggest single-benchmark swing is WeirdML: 57.1% for GLM-5.1 and 42.9% for Grok 4 Fast.
  • GLM-5.1 has downloadable open weights; the other is API-only.

Side by side

GLM-5.1Grok 4 Fast
ProviderZ.ai (Zhipu)xAI
Noometry Index47.839.4
Released2026-04-072025-09-19
WeightsOpenProprietary
Context window200K—
Max output131K—
Input $ / M tokens$1.40—
Output $ / M tokens$4.40—
Results tracked4130

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Category by category

Coding GLM-5.1 leads

GLM-5.1: 48.7 (#55), Grok 4 Fast: 32.5 (#271)

BenchmarkGLM-5.1Grok 4 Fast
LMArena WebDev15081159
WeirdML57.1%42.9%
LMArena Coding14851429
SWE-bench Verified74.2%—
SciCode43.8%—
ALE-Bench887.1—

Agentic & Tool Use Grok 4 Fast leads

GLM-5.1: 24.9 (#113), Grok 4 Fast: 29.5 (#86)

BenchmarkGLM-5.1Grok 4 Fast
APEX-Agents40.9%—
τ²-bench Banking—15.7%
Cybench—30%
ExploitBench18.1%—
GBAEval0%—
LMArena Search—1171
Vending-Bench 25,634—

Reasoning GLM-5.1 leads

GLM-5.1: 39.1 (#60), Grok 4 Fast: 22.2 (#201)

BenchmarkGLM-5.1Grok 4 Fast
LMArena Hard Prompts14721412
Epoch Capabilities Index149.84144.2
ARC-AGI-2—5.3%
SimpleBench55.1%—
Kagi LLM Benchmark—66.1%
NYT Connections (extended)77.7%—
ARC-AGI-1—48.5%
CritPt4.6%—
Chess Puzzles19%—
Thematic Generalization69.8%—
DTBench—82.7%
ForecastBench—60.5

Math GLM-5.1 leads

GLM-5.1: 49.7 (#60), Grok 4 Fast: 38.9 (#123)

BenchmarkGLM-5.1Grok 4 Fast
LMArena Math14731419
FrontierMath (Tiers 1-3)36.8%—
MathArena Final-Answer Competitions67.1%—
OTIS Mock AIME 2024-202593.3%—
ProofBench22.2%—
FrontierMath (Feb 2025 set)33.4%—
FrontierMath Tier 4 (v1)12.5%—

Knowledge GLM-5.1 leads

GLM-5.1: 54.9 (#50), Grok 4 Fast: 32.0 (#214)

BenchmarkGLM-5.1Grok 4 Fast
LMArena Expert14761411
GPQA Diamond89.9%—
SimpleQA Verified34%—
Vectara Hallucination Rate—19.7%

Multilingual GLM-5.1 leads

GLM-5.1: 55.0 (#36), Grok 4 Fast: 51.3 (#111)

BenchmarkGLM-5.1Grok 4 Fast
LMArena Non-English14471396
LMArena Chinese15151457
LMArena French14741431
LMArena German14651383
LMArena Japanese14341352
LMArena Korean14181357
LMArena Russian14541389
LMArena Spanish14691415

Instruction Following GLM-5.1 leads

GLM-5.1: 76.3 (#42), Grok 4 Fast: 73.2 (#121)

BenchmarkGLM-5.1Grok 4 Fast
LMArena Instruction Following14511387

Long Context Grok 4 Fast leads

GLM-5.1: 44.9 (#53), Grok 4 Fast: 63.2 (#3)

BenchmarkGLM-5.1Grok 4 Fast
LMArena Longer Query14661415
Fiction.LiveBench—94.4%

Writing & Preference GLM-5.1 leads

GLM-5.1: 66.9 (#31), Grok 4 Fast: 60.0 (#102)

BenchmarkGLM-5.1Grok 4 Fast
LMArena Text14611407
LMArena Creative Writing14531387
LMArena Multi-Turn14721414
EQ-Bench Creative Writing1592—

Frequently asked questions

Is GLM-5.1 better than Grok 4 Fast?

GLM-5.1 is the stronger model overall, scoring 47.8 to 39.4 on the Noometry Index.

Is GLM-5.1 or Grok 4 Fast better for coding?

GLM-5.1 scores higher on coding benchmarks: 48.7 versus 32.5 in the Noometry coding category.

How many benchmarks do GLM-5.1 and Grok 4 Fast share?

20 benchmarks have published results for both models. GLM-5.1 has 41 scored results on Noometry and Grok 4 Fast has 30.

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