Noometry

Model comparison

Claude Opus 5.5 vs Grok-2 (Dec 2024)

Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 33.7 on the Noometry Index.

Last verified . 18 shared benchmarks.

Claude Opus 5.5 Anthropic

68.6

Rank #3 Confirmed

Grok-2 (Dec 2024) xAI

33.7

Rank #239 Confirmed

Summary

  • They share 18 benchmarks with published results for both. Claude Opus 5.5 scores higher in 8 categories and Grok-2 (Dec 2024) in 0 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in math, where Claude Opus 5.5 leads 91.8 to 20.8.
  • The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 100% for Claude Opus 5.5 and 11.5% for Grok-2 (Dec 2024).

Side by side

Claude Opus 5.5Grok-2 (Dec 2024)
ProviderAnthropicxAI
Noometry Index68.633.7
Released2026-09-222024-08-13
WeightsProprietaryProprietary
Context window1M—
Max output128K—
Input $ / M tokens$4—
Output $ / M tokens$20—
Results tracked4434

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Category by category

Coding Claude Opus 5.5 leads

Claude Opus 5.5: 71.9 (#3), Grok-2 (Dec 2024): 33.3 (#258)

BenchmarkClaude Opus 5.5Grok-2 (Dec 2024)
LMArena Coding15471287
FrontierCode54.6%—
CursorBench57.8%—
LMArena WebDev1813—
FrontierSWE62.3%—
SciCode66.9%—
WeirdML—22.2%
LiveBench Coding—46.4%
MirrorCode77.4%—
ALE-Bench2,147—

Agentic & Tool Use Not comparable

Claude Opus 5.5: 45.3 (#15), Grok-2 (Dec 2024): —

BenchmarkClaude Opus 5.5Grok-2 (Dec 2024)
APEX-Agents73.5%—
GDP.pdf30.6%—
Vending-Bench 29,235—

Reasoning Claude Opus 5.5 leads

Claude Opus 5.5: 80.2 (#3), Grok-2 (Dec 2024): 16.9 (#299)

BenchmarkClaude Opus 5.5Grok-2 (Dec 2024)
LMArena Hard Prompts15351272
DTBench98.9%65.2%
Epoch Capabilities Index167.33130.48
ARC-AGI-293.3%—
SimpleBench—22.7%
NYT Connections (extended)88.5%—
ARC-AGI-198.5%—
CritPt31.7%—
EBR-Bench71.4%—
LiveBench Reasoning—54.8%
Mystery Game Puzzles71%—
LiveBench Data Analysis—54.5%
LMCA68.2%—
LiveBench—54.3%

Math Claude Opus 5.5 leads

Claude Opus 5.5: 91.8 (#3), Grok-2 (Dec 2024): 20.8 (#284)

BenchmarkClaude Opus 5.5Grok-2 (Dec 2024)
OTIS Mock AIME 2024-2025100%11.5%
LMArena Math15061283
FrontierMath (Tiers 1-3)91.2%—
FrontierMath Tier 495%—
ProofBench100%—
LiveBench Math—54.9%
MATH Level 5—63.5%
FrontierMath (Feb 2025 set)—0.7%
FrontierMath Erdős2.9%—

Knowledge Claude Opus 5.5 leads

Claude Opus 5.5: 66.4 (#10), Grok-2 (Dec 2024): 29.8 (#233)

BenchmarkClaude Opus 5.5Grok-2 (Dec 2024)
GPQA Diamond90.6%53.8%
LMArena Expert15471254
SimpleQA Verified72.2%—
Confabulations—20.1%

Multimodal Not comparable

Claude Opus 5.5: 57.8 (#1), Grok-2 (Dec 2024): —

BenchmarkClaude Opus 5.5Grok-2 (Dec 2024)
LMArena Vision1321—
Blueprint-Bench 251.2%—
Furniture Assembly83.3%—

Multilingual Claude Opus 5.5 leads

Claude Opus 5.5: 59.1 (#2), Grok-2 (Dec 2024): 43.1 (#188)

BenchmarkClaude Opus 5.5Grok-2 (Dec 2024)
LMArena Non-English15071282
LMArena Chinese15881289
LMArena French15141318
LMArena Russian15201286
LMArena Spanish15071281
LMArena German—1287
LMArena Japanese—1244
LMArena Korean—1237

Instruction Following Claude Opus 5.5 leads

Claude Opus 5.5: 80.0 (#3), Grok-2 (Dec 2024): 66.9 (#202)

BenchmarkClaude Opus 5.5Grok-2 (Dec 2024)
LMArena Instruction Following15371270
LiveBench Instruction Following—69.6%

Long Context Claude Opus 5.5 leads

Claude Opus 5.5: 47.1 (#19), Grok-2 (Dec 2024): 38.8 (#190)

BenchmarkClaude Opus 5.5Grok-2 (Dec 2024)
LMArena Longer Query15321276

Writing & Preference Claude Opus 5.5 leads

Claude Opus 5.5: 78.2 (#3), Grok-2 (Dec 2024): 48.6 (#198)

BenchmarkClaude Opus 5.5Grok-2 (Dec 2024)
LMArena Text15151305
LMArena Creative Writing15331284
LMArena Multi-Turn14991290
Short-Story Creative Writing—63.6%
EQ-Bench Creative Writing2050—
LiveBench Language—45.6%

Frequently asked questions

Is Claude Opus 5.5 better than Grok-2 (Dec 2024)?

Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 33.7 on the Noometry Index.

Is Claude Opus 5.5 or Grok-2 (Dec 2024) better for coding?

Claude Opus 5.5 scores higher on coding benchmarks: 71.9 versus 33.3 in the Noometry coding category.

How many benchmarks do Claude Opus 5.5 and Grok-2 (Dec 2024) share?

18 benchmarks have published results for both models. Claude Opus 5.5 has 44 scored results on Noometry and Grok-2 (Dec 2024) has 34.

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