Noometry

Model comparison

GPT-5.6 Terra vs Grok 4 Fast

GPT-5.6 Terra is the stronger model overall, scoring 59.2 to 39.4 on the Noometry Index.

Last verified . 24 shared benchmarks.

GPT-5.6 Terra OpenAI

59.2

Rank #17 Confirmed

Grok 4 Fast xAI

39.4

Rank #167 Confirmed

Summary

  • They share 24 benchmarks with published results for both. GPT-5.6 Terra scores higher in 8 categories and Grok 4 Fast in 1 category; 9 gaps are clear of the uncertainty.
  • The widest gap is in math, where GPT-5.6 Terra leads 81.6 to 38.9.
  • The biggest single-benchmark swing is ARC-AGI-2: 83.9% for GPT-5.6 Terra and 5.3% for Grok 4 Fast.

Side by side

GPT-5.6 TerraGrok 4 Fast
ProviderOpenAIxAI
Noometry Index59.239.4
Released2026-07-092025-09-19
WeightsProprietaryProprietary
Context window1.05M—
Max output128K—
Input $ / M tokens$2—
Output $ / M tokens$12—
Results tracked5230

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Category by category

Coding GPT-5.6 Terra leads

GPT-5.6 Terra: 57.7 (#19), Grok 4 Fast: 32.5 (#271)

BenchmarkGPT-5.6 TerraGrok 4 Fast
LMArena WebDev15221159
WeirdML78.3%42.9%
LMArena Coding14841429
DeepSWE69.6%—
FrontierCode41.3%—
CursorBench41.3%—
SciCode55%—
ALE-Bench1,951—

Agentic & Tool Use GPT-5.6 Terra leads

GPT-5.6 Terra: 40.1 (#25), Grok 4 Fast: 29.5 (#86)

BenchmarkGPT-5.6 TerraGrok 4 Fast
APEX-Agents58.2%—
τ²-bench Banking—15.7%
Cybench—30%
BALROG53.2%—
GDP.pdf24.7%—
LMArena Search—1171
Vending-Bench 27,343—

Reasoning GPT-5.6 Terra leads

GPT-5.6 Terra: 60.7 (#21), Grok 4 Fast: 22.2 (#201)

BenchmarkGPT-5.6 TerraGrok 4 Fast
ARC-AGI-283.9%5.3%
Kagi LLM Benchmark51.3%66.1%
ARC-AGI-196.5%48.5%
LMArena Hard Prompts14681412
DTBench93.3%82.7%
Epoch Capabilities Index159.62144.2
SimpleBench48.9%—
NYT Connections (extended)78.4%—
CritPt30%—
Chess Puzzles54%—
Mystery Game Puzzles35%—
LMCA55%—
Surface Evolver Bench83.8%—
ForecastBench—60.5

Math GPT-5.6 Terra leads

GPT-5.6 Terra: 81.6 (#12), Grok 4 Fast: 38.9 (#123)

BenchmarkGPT-5.6 TerraGrok 4 Fast
LMArena Math14661419
FrontierMath (Tiers 1-3)86%—
FrontierMath Tier 470.7%—
OTIS Mock AIME 2024-202599.7%—
ProofBench74%—

Knowledge GPT-5.6 Terra leads

GPT-5.6 Terra: 61.2 (#30), Grok 4 Fast: 32.0 (#214)

BenchmarkGPT-5.6 TerraGrok 4 Fast
LMArena Expert14921411
GPQA Diamond93.3%—
SimpleQA Verified43.2%—
Vectara Hallucination Rate—19.7%

Multimodal Not comparable

GPT-5.6 Terra: 47.3 (#11), Grok 4 Fast: —

BenchmarkGPT-5.6 TerraGrok 4 Fast
LMArena Vision1271—
Blueprint-Bench 230.8%—
Furniture Assembly54.2%—
LMArena Document1472—

Multilingual GPT-5.6 Terra leads

GPT-5.6 Terra: 54.4 (#44), Grok 4 Fast: 51.3 (#111)

BenchmarkGPT-5.6 TerraGrok 4 Fast
LMArena Non-English14391396
LMArena Chinese15131457
LMArena French14711431
LMArena German14601383
LMArena Japanese14571352
LMArena Korean14251357
LMArena Russian14501389
LMArena Spanish14481415

Instruction Following GPT-5.6 Terra leads

GPT-5.6 Terra: 76.4 (#40), Grok 4 Fast: 73.2 (#121)

BenchmarkGPT-5.6 TerraGrok 4 Fast
LMArena Instruction Following14541387

Long Context Grok 4 Fast leads

GPT-5.6 Terra: 44.4 (#68), Grok 4 Fast: 63.2 (#3)

BenchmarkGPT-5.6 TerraGrok 4 Fast
LMArena Longer Query14511415
Fiction.LiveBench—94.4%

Writing & Preference GPT-5.6 Terra leads

GPT-5.6 Terra: 70.2 (#23), Grok 4 Fast: 60.0 (#102)

BenchmarkGPT-5.6 TerraGrok 4 Fast
LMArena Text14471407
LMArena Creative Writing14101387
LMArena Multi-Turn14491414
EQ-Bench Creative Writing1855—
EQ-Bench 41234—

Frequently asked questions

Is GPT-5.6 Terra better than Grok 4 Fast?

GPT-5.6 Terra is the stronger model overall, scoring 59.2 to 39.4 on the Noometry Index.

Is GPT-5.6 Terra or Grok 4 Fast better for coding?

GPT-5.6 Terra scores higher on coding benchmarks: 57.7 versus 32.5 in the Noometry coding category.

How many benchmarks do GPT-5.6 Terra and Grok 4 Fast share?

24 benchmarks have published results for both models. GPT-5.6 Terra has 52 scored results on Noometry and Grok 4 Fast has 30.

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