Model comparison

GPT-5 Nano vs Molmo 2 8b

Molmo 2 8b is the stronger model overall, scoring 39.1 to 33.5 on the Noometry Index.

Last verified . 5 shared benchmarks.

GPT-5 Nano OpenAI

33.5

Rank #241 Confirmed

Summary

  • They share 5 benchmarks with published results for both. GPT-5 Nano scores higher in 3 categories and Molmo 2 8b in 2 categories; 5 gaps are clear of the uncertainty.
  • The widest gap is in writing & preference, where Molmo 2 8b leads 49.4 to 39.1.
  • Molmo 2 8b has downloadable open weights; the other is API-only.

Side by side

GPT-5 Nano and Molmo 2 8b specifications
GPT-5 NanoMolmo 2 8b
ProviderOpenAIAllen Institute for AI (Ai2)
Noometry Index33.539.1
Released2025-08-07—
WeightsProprietaryOpen
Context window400K—
Max output128K—
Input $ / M tokens$0.05—
Output $ / M tokens$0.40—
Results tracked495

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Category by category

Coding Not comparable

GPT-5 Nano: 33.6 (#254), Molmo 2 8b: —

Coding benchmarks
BenchmarkGPT-5 NanoMolmo 2 8b
SWE-bench Verified (bash only)34.8%—
WeirdML38.1%—
LMArena Coding1351—
ALE-Bench718.67—

Agentic & Tool Use Not comparable

GPT-5 Nano: 25.8 (#106), Molmo 2 8b: —

Agentic & Tool Use benchmarks
BenchmarkGPT-5 NanoMolmo 2 8b
Terminal-Bench21.8%—
Berkeley Function Calling Leaderboard51.5%—

Reasoning Molmo 2 8b leads

GPT-5 Nano: 16.3 (#306), Molmo 2 8b: 25.6 (#146)

Reasoning benchmarks
BenchmarkGPT-5 NanoMolmo 2 8b
LMArena Hard Prompts13281287
ARC-AGI-22.6%—
Kagi LLM Benchmark62.2%—
ARC-AGI-120.7%—
Chess Puzzles27%—
Mystery Game Puzzles9%—
DTBench62.7%—
LMCA7.9%—
Epoch Capabilities Index139.38—
ForecastBench59.1—

Math Not comparable

GPT-5 Nano: 29.4 (#241), Molmo 2 8b: —

Math benchmarks
BenchmarkGPT-5 NanoMolmo 2 8b
FrontierMath (Tiers 1-3)20%—
FrontierMath Tier 42.4%—
OTIS Mock AIME 2024-202581.1%—
ProofBench12%—
Omni-MATH54.6%—
LMArena Math1317—
MATH Level 595.2%—
FrontierMath (Feb 2025 set)8.3%—
FrontierMath Tier 4 (v1)2.1%—

Knowledge Not comparable

GPT-5 Nano: 35.9 (#178), Molmo 2 8b: —

Knowledge benchmarks
BenchmarkGPT-5 NanoMolmo 2 8b
GPQA Diamond69.4%—
SimpleQA Verified11.7%—
MMLU-Pro77.8%—
Vectara Hallucination Rate10.5%—
GPQA (HELM)67.9%—
LMArena Expert1321—

Multimodal GPT-5 Nano leads

GPT-5 Nano: 31.3 (#108), Molmo 2 8b: 30.2 (#112)

Multimodal benchmarks
BenchmarkGPT-5 NanoMolmo 2 8b
LMArena Vision11591081
VPCT37.2%—

Multilingual GPT-5 Nano leads

GPT-5 Nano: 45.3 (#172), Molmo 2 8b: 42.7 (#190)

Multilingual benchmarks
BenchmarkGPT-5 NanoMolmo 2 8b
LMArena Non-English13131276
LMArena Chinese1356—
LMArena German1327—
LMArena Japanese1226—
LMArena Korean1269—
LMArena Russian1296—
LMArena Spanish1360—

Instruction Following GPT-5 Nano leads

GPT-5 Nano: 75.0 (#79), Molmo 2 8b: 67.0 (#201)

Instruction Following benchmarks
BenchmarkGPT-5 NanoMolmo 2 8b
LMArena Instruction Following13061270
IFEval93.2%—

Long Context Not comparable

GPT-5 Nano: 31.3 (#281), Molmo 2 8b: —

Long Context benchmarks
BenchmarkGPT-5 NanoMolmo 2 8b
Fiction.LiveBench44.4%—
LMArena Longer Query1312—

Writing & Preference Molmo 2 8b leads

GPT-5 Nano: 39.1 (#249), Molmo 2 8b: 49.4 (#191)

Writing & Preference benchmarks
BenchmarkGPT-5 NanoMolmo 2 8b
LMArena Text13201288
LMArena Creative Writing1249—
EQ-Bench Creative Writing705—
WildBench80.6%—
LMArena Multi-Turn1311—

Frequently asked questions

Is GPT-5 Nano better than Molmo 2 8b?

Molmo 2 8b is the stronger model overall, scoring 39.1 to 33.5 on the Noometry Index.

How many benchmarks do GPT-5 Nano and Molmo 2 8b share?

5 benchmarks have published results for both models. GPT-5 Nano has 49 scored results on Noometry and Molmo 2 8b has 5.

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