Model comparison

Granite 3.1 2b Instruct vs Grok 4 Fast

Grok 4 Fast is the stronger model overall, scoring 39.0 to 32.6 on the Noometry Index.

Last verified . 12 shared benchmarks.

Granite 3.1 2b Instruct IBM

32.6

Rank #243 Confirmed

Grok 4 Fast xAI

39.0

Rank #164 Confirmed

Summary

  • They share 12 benchmarks with published results for both. Granite 3.1 2b Instruct scores higher in 1 category and Grok 4 Fast in 7 categories; 7 gaps are clear of the uncertainty.
  • The widest gap is in long context, where Grok 4 Fast leads 63.2 to 35.0.
  • Granite 3.1 2b Instruct has downloadable open weights; the other is API-only.

Side by side

Granite 3.1 2b Instruct and Grok 4 Fast specifications
Granite 3.1 2b InstructGrok 4 Fast
ProviderIBMxAI
Noometry Index32.639.0
Released—2025-09-19
WeightsOpenProprietary
Context window——
Max output——
Input $ / M tokens——
Output $ / M tokens——
Results tracked1230

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Category by category

Coding Too close to call

Granite 3.1 2b Instruct: 32.9 (#255), Grok 4 Fast: 32.3 (#264)

Coding benchmarks
BenchmarkGranite 3.1 2b InstructGrok 4 Fast
LMArena Coding11491429
LMArena WebDev—1160
WeirdML—42.9%

Agentic & Tool Use Not comparable

Granite 3.1 2b Instruct: —, Grok 4 Fast: 29.3 (#80)

Agentic & Tool Use benchmarks
BenchmarkGranite 3.1 2b InstructGrok 4 Fast
τ²-bench Banking—15.7%
Cybench—30%
LMArena Search—1171

Reasoning Grok 4 Fast leads

Granite 3.1 2b Instruct: 21.0 (#206), Grok 4 Fast: 22.5 (#179)

Reasoning benchmarks
BenchmarkGranite 3.1 2b InstructGrok 4 Fast
LMArena Hard Prompts11381413
ARC-AGI-2—5.3%
Kagi LLM Benchmark—66.1%
ARC-AGI-1—48.5%
DTBench—82.7%
Epoch Capabilities Index—144.21
ForecastBench—60.5

Math Grok 4 Fast leads

Granite 3.1 2b Instruct: 30.6 (#206), Grok 4 Fast: 36.1 (#126)

Math benchmarks
BenchmarkGranite 3.1 2b InstructGrok 4 Fast
LMArena Math11591419

Knowledge Grok 4 Fast leads

Granite 3.1 2b Instruct: 30.3 (#223), Grok 4 Fast: 31.5 (#211)

Knowledge benchmarks
BenchmarkGranite 3.1 2b InstructGrok 4 Fast
LMArena Expert11311411
Vectara Hallucination Rate—19.7%

Multilingual Grok 4 Fast leads

Granite 3.1 2b Instruct: 29.2 (#264), Grok 4 Fast: 51.5 (#106)

Multilingual benchmarks
BenchmarkGranite 3.1 2b InstructGrok 4 Fast
LMArena Non-English10681397
LMArena Chinese11381458
LMArena Russian10631387
LMArena French—1433
LMArena German—1383
LMArena Japanese—1358
LMArena Korean—1359
LMArena Spanish—1414

Instruction Following Grok 4 Fast leads

Granite 3.1 2b Instruct: 58.0 (#259), Grok 4 Fast: 73.4 (#116)

Instruction Following benchmarks
BenchmarkGranite 3.1 2b InstructGrok 4 Fast
LMArena Instruction Following11161388

Long Context Grok 4 Fast leads

Granite 3.1 2b Instruct: 35.0 (#239), Grok 4 Fast: 63.2 (#3)

Long Context benchmarks
BenchmarkGranite 3.1 2b InstructGrok 4 Fast
LMArena Longer Query11551415
Fiction.LiveBench—94.4%

Writing & Preference Grok 4 Fast leads

Granite 3.1 2b Instruct: 34.3 (#269), Grok 4 Fast: 60.2 (#96)

Writing & Preference benchmarks
BenchmarkGranite 3.1 2b InstructGrok 4 Fast
LMArena Text11271407
LMArena Creative Writing11161388
LMArena Multi-Turn10991414

Frequently asked questions

Is Granite 3.1 2b Instruct better than Grok 4 Fast?

Grok 4 Fast is the stronger model overall, scoring 39.0 to 32.6 on the Noometry Index.

Is Granite 3.1 2b Instruct or Grok 4 Fast better for coding?

They score almost the same on coding (32.9 vs 32.3); test both on your own repository before choosing.

How many benchmarks do Granite 3.1 2b Instruct and Grok 4 Fast share?

12 benchmarks have published results for both models. Granite 3.1 2b Instruct has 12 scored results on Noometry and Grok 4 Fast has 30.

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