Noometry

Model comparison

GPT-5.1-Codex vs Qwen3.5 27B

Qwen3.5 27B is the stronger model overall, scoring 41.4 to 38.2 on the Noometry Index.

Last verified . 2 shared benchmarks.

GPT-5.1-Codex OpenAI

38.2

Rank #178 Reported

Qwen3.5 27B Alibaba (Qwen)

41.4

Rank #127 Confirmed

Summary

  • They share 2 benchmarks with published results for both. GPT-5.1-Codex scores higher in 1 category and Qwen3.5 27B in 1 category; 2 gaps are clear of the uncertainty.
  • The widest gap is in math, where Qwen3.5 27B leads 36.8 to 29.3.
  • Qwen3.5 27B is cheaper at $0.30 / $2.40 per million input/output tokens, against $1.25 / $10 for GPT-5.1-Codex.
  • GPT-5.1-Codex accepts more context: 400K tokens versus 262K.
  • Qwen3.5 27B has downloadable open weights; the other is API-only.

Side by side

GPT-5.1-CodexQwen3.5 27B
ProviderOpenAIAlibaba (Qwen)
Noometry Index38.241.4
Released2025-11-122026-02-23
WeightsProprietaryOpen
Context window400K262K
Max output128K66K
Input $ / M tokens$1.25$0.30
Output $ / M tokens$10$2.40
Results tracked628

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Category by category

Coding GPT-5.1-Codex leads

GPT-5.1-Codex: 41.7 (#107), Qwen3.5 27B: 38.6 (#159)

BenchmarkGPT-5.1-CodexQwen3.5 27B
LMArena WebDev13371357
ALE-Bench1,245349.45
SWE-bench Verified (bash only)66%—
WeirdML—39.5%
LMArena Coding—1427

Agentic & Tool Use Not comparable

GPT-5.1-Codex: 37.8 (#32), Qwen3.5 27B: —

BenchmarkGPT-5.1-CodexQwen3.5 27B
Terminal-Bench60.4%—
METR Time Horizons70.8%—
Vending-Bench 2—201.98

Reasoning Not comparable

GPT-5.1-Codex: —, Qwen3.5 27B: 26.6 (#116)

BenchmarkGPT-5.1-CodexQwen3.5 27B
NYT Connections (extended)—47.9%
Thematic Generalization—45.5%
LMArena Hard Prompts—1414
DTBench—82.4%
LMCA—34%

Math Qwen3.5 27B leads

GPT-5.1-Codex: 29.3 (#218), Qwen3.5 27B: 36.8 (#103)

BenchmarkGPT-5.1-CodexQwen3.5 27B
MathArena Final-Answer Competitions—56.7%
ProofBench9%—
LMArena Math—1428

Knowledge Not comparable

GPT-5.1-Codex: —, Qwen3.5 27B: 37.4 (#149)

BenchmarkGPT-5.1-CodexQwen3.5 27B
Vectara Hallucination Rate—12.1%
LMArena Expert—1428

Multimodal Not comparable

GPT-5.1-Codex: —, Qwen3.5 27B: 38.7 (#56)

BenchmarkGPT-5.1-CodexQwen3.5 27B
LMArena Vision—1240

Multilingual Not comparable

GPT-5.1-Codex: —, Qwen3.5 27B: 51.0 (#112)

BenchmarkGPT-5.1-CodexQwen3.5 27B
LMArena Non-English—1390
LMArena Chinese—1478
LMArena French—1409
LMArena German—1393
LMArena Japanese—1345
LMArena Korean—1359
LMArena Russian—1389
LMArena Spanish—1408

Instruction Following Not comparable

GPT-5.1-Codex: —, Qwen3.5 27B: 73.7 (#114)

BenchmarkGPT-5.1-CodexQwen3.5 27B
LMArena Instruction Following—1393

Long Context Not comparable

GPT-5.1-Codex: —, Qwen3.5 27B: 43.1 (#103)

BenchmarkGPT-5.1-CodexQwen3.5 27B
LMArena Longer Query—1413

Writing & Preference Not comparable

GPT-5.1-Codex: —, Qwen3.5 27B: 59.5 (#106)

BenchmarkGPT-5.1-CodexQwen3.5 27B
LMArena Text—1409
LMArena Creative Writing—1362
LMArena Multi-Turn—1410

Frequently asked questions

Is GPT-5.1-Codex better than Qwen3.5 27B?

Qwen3.5 27B is the stronger model overall, scoring 41.4 to 38.2 on the Noometry Index.

Which is cheaper, GPT-5.1-Codex or Qwen3.5 27B?

Qwen3.5 27B is cheaper. It lists at $0.30 per million input tokens and $2.40 per million output tokens; GPT-5.1-Codex lists at $1.25 and $10.

Is GPT-5.1-Codex or Qwen3.5 27B better for coding?

GPT-5.1-Codex scores higher on coding benchmarks: 41.7 versus 38.6 in the Noometry coding category.

Which has the bigger context window?

GPT-5.1-Codex does, with 400K tokens against 262K.

How many benchmarks do GPT-5.1-Codex and Qwen3.5 27B share?

2 benchmarks have published results for both models. GPT-5.1-Codex has 6 scored results on Noometry and Qwen3.5 27B has 28.

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