Noometry

Model comparison

Grok 4 Fast vs Muse Spark 1.2

Muse Spark 1.2 is the stronger model overall, scoring 50.3 to 39.4 on the Noometry Index.

Last verified . 18 shared benchmarks.

Grok 4 Fast xAI

39.4

Rank #167 Confirmed

Muse Spark 1.2 Meta

50.3

Rank #48 Confirmed

Summary

  • They share 18 benchmarks with published results for both. Grok 4 Fast scores higher in 2 categories and Muse Spark 1.2 in 7 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Muse Spark 1.2 leads 51.3 to 22.2.
  • The biggest single-benchmark swing is WeirdML: 42.9% for Grok 4 Fast and 60.3% for Muse Spark 1.2.

Side by side

Grok 4 FastMuse Spark 1.2
ProviderxAIMeta
Noometry Index39.450.3
Released2025-09-192026-08-05
WeightsProprietaryProprietary
Context window—1.05M
Max output—131K
Input $ / M tokens—$1.25
Output $ / M tokens—$4.25
Results tracked3031

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Category by category

Coding Muse Spark 1.2 leads

Grok 4 Fast: 32.5 (#271), Muse Spark 1.2: 49.2 (#51)

BenchmarkGrok 4 FastMuse Spark 1.2
LMArena WebDev11591533
WeirdML42.9%60.3%
LMArena Coding14291495
DeepSWE—54.9%
FrontierSWE—12%
SciCode—56.4%

Agentic & Tool Use Too close to call

Grok 4 Fast: 29.5 (#86), Muse Spark 1.2: 29.4 (#87)

BenchmarkGrok 4 FastMuse Spark 1.2
APEX-Agents—36.4%
τ²-bench Banking15.7%—
Cybench30%—
GDP.pdf—16%
LMArena Search1171—

Reasoning Muse Spark 1.2 leads

Grok 4 Fast: 22.2 (#201), Muse Spark 1.2: 51.3 (#34)

BenchmarkGrok 4 FastMuse Spark 1.2
LMArena Hard Prompts14121486
DTBench82.7%94.7%
Epoch Capabilities Index144.2154.87
ARC-AGI-25.3%—
SimpleBench—74.5%
Kagi LLM Benchmark66.1%—
NYT Connections (extended)—79.2%
ARC-AGI-148.5%—
CritPt—17.7%
LMCA—48.4%
ForecastBench60.5—

Math Muse Spark 1.2 leads

Grok 4 Fast: 38.9 (#123), Muse Spark 1.2: 46.4 (#70)

BenchmarkGrok 4 FastMuse Spark 1.2
LMArena Math14191471
ProofBench—43%

Knowledge Muse Spark 1.2 leads

Grok 4 Fast: 32.0 (#214), Muse Spark 1.2: 54.1 (#53)

BenchmarkGrok 4 FastMuse Spark 1.2
LMArena Expert14111480
SimpleQA Verified—60.3%
Vectara Hallucination Rate19.7%—

Multimodal Not comparable

Grok 4 Fast: —, Muse Spark 1.2: 43.4 (#25)

BenchmarkGrok 4 FastMuse Spark 1.2
LMArena Vision—1305

Multilingual Muse Spark 1.2 leads

Grok 4 Fast: 51.3 (#111), Muse Spark 1.2: 57.1 (#11)

BenchmarkGrok 4 FastMuse Spark 1.2
LMArena Non-English13961478
LMArena Chinese14571511
LMArena French14311513
LMArena Russian13891487
LMArena Spanish14151498
LMArena German1383—
LMArena Japanese1352—
LMArena Korean1357—

Instruction Following Muse Spark 1.2 leads

Grok 4 Fast: 73.2 (#121), Muse Spark 1.2: 76.7 (#36)

BenchmarkGrok 4 FastMuse Spark 1.2
LMArena Instruction Following13871461

Long Context Grok 4 Fast leads

Grok 4 Fast: 63.2 (#3), Muse Spark 1.2: 45.2 (#48)

BenchmarkGrok 4 FastMuse Spark 1.2
LMArena Longer Query14151475
Fiction.LiveBench94.4%—

Writing & Preference Muse Spark 1.2 leads

Grok 4 Fast: 60.0 (#102), Muse Spark 1.2: 72.3 (#14)

BenchmarkGrok 4 FastMuse Spark 1.2
LMArena Text14071482
LMArena Creative Writing13871449
LMArena Multi-Turn14141494
EQ-Bench Creative Writing—1840

Frequently asked questions

Is Grok 4 Fast better than Muse Spark 1.2?

Muse Spark 1.2 is the stronger model overall, scoring 50.3 to 39.4 on the Noometry Index.

Is Grok 4 Fast or Muse Spark 1.2 better for coding?

Muse Spark 1.2 scores higher on coding benchmarks: 49.2 versus 32.5 in the Noometry coding category.

How many benchmarks do Grok 4 Fast and Muse Spark 1.2 share?

18 benchmarks have published results for both models. Grok 4 Fast has 30 scored results on Noometry and Muse Spark 1.2 has 31.

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