Noometry

Model comparison

GLM-5.3-Flash vs GPT-5.1-Codex

GLM-5.3-Flash is the stronger model overall, scoring 51.8 to 38.6 on the Noometry Index.

Last verified . 3 shared benchmarks.

GLM-5.3-Flash Z.ai (Zhipu)

51.8

Rank #41 Confirmed

GPT-5.1-Codex OpenAI

38.6

Rank #186 Reported

Summary

  • They share 3 benchmarks with published results for both. GLM-5.3-Flash scores higher in 2 categories and GPT-5.1-Codex in 1 category; 3 gaps are clear of the uncertainty.
  • The widest gap is in math, where GLM-5.3-Flash leads 53.3 to 30.3.
  • The biggest single-benchmark swing is ProofBench: 21% for GLM-5.3-Flash and 9% for GPT-5.1-Codex.
  • GLM-5.3-Flash is cheaper at $0.15 / $0.50 per million input/output tokens, against $1.25 / $10 for GPT-5.1-Codex.
  • GLM-5.3-Flash accepts more context: 1M tokens versus 400K.
  • GLM-5.3-Flash has downloadable open weights; the other is API-only.

Side by side

GLM-5.3-FlashGPT-5.1-Codex
ProviderZ.ai (Zhipu)OpenAI
Noometry Index51.838.6
Released2026-08-202025-11-12
WeightsOpenProprietary
Context window1M400K
Max output131K128K
Input $ / M tokens$0.15$1.25
Output $ / M tokens$0.50$10
Results tracked406

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Category by category

Coding GLM-5.3-Flash leads

GLM-5.3-Flash: 53.1 (#31), GPT-5.1-Codex: 41.9 (#116)

BenchmarkGLM-5.3-FlashGPT-5.1-Codex
LMArena WebDev16091337
ALE-Bench303.551,245
DeepSWE63.4%—
FrontierCode31.8%—
SWE-bench Verified (bash only)—66%
CursorBench36.8%—
FrontierSWE18.1%—
SciCode51.6%—
LMArena Coding1508—

Agentic & Tool Use GPT-5.1-Codex leads

GLM-5.3-Flash: 34.2 (#47), GPT-5.1-Codex: 38.0 (#33)

BenchmarkGLM-5.3-FlashGPT-5.1-Codex
Terminal-Bench—60.4%
APEX-Agents52.8%—
GDP.pdf14%—
METR Time Horizons—70.8%

Reasoning Not comparable

GLM-5.3-Flash: 48.0 (#42), GPT-5.1-Codex: —

BenchmarkGLM-5.3-FlashGPT-5.1-Codex
ARC-AGI-265.8%—
ARC-AGI-191%—
CritPt15.4%—
Chess Puzzles14%—
LMArena Hard Prompts1491—
Mystery Game Puzzles8%—
Surface Evolver Bench52.5%—
Bench to the Future 30.15—
Epoch Capabilities Index151.88—

Math GLM-5.3-Flash leads

GLM-5.3-Flash: 53.3 (#47), GPT-5.1-Codex: 30.3 (#235)

BenchmarkGLM-5.3-FlashGPT-5.1-Codex
ProofBench21%9%
FrontierMath (Tiers 1-3)55.8%—
FrontierMath Tier 417.1%—
OTIS Mock AIME 2024-202593.9%—
LMArena Math1500—

Knowledge Not comparable

GLM-5.3-Flash: 58.4 (#36), GPT-5.1-Codex: —

BenchmarkGLM-5.3-FlashGPT-5.1-Codex
GPQA Diamond90.2%—
LMArena Expert1513—

Multimodal Not comparable

GLM-5.3-Flash: 42.8 (#27), GPT-5.1-Codex: —

BenchmarkGLM-5.3-FlashGPT-5.1-Codex
LMArena Vision1296—

Multilingual Not comparable

GLM-5.3-Flash: 56.0 (#25), GPT-5.1-Codex: —

BenchmarkGLM-5.3-FlashGPT-5.1-Codex
LMArena Non-English1462—
LMArena Chinese1527—
LMArena French1496—
LMArena German1470—
LMArena Japanese1429—
LMArena Korean1446—
LMArena Russian1469—
LMArena Spanish1471—

Instruction Following Not comparable

GLM-5.3-Flash: 77.5 (#20), GPT-5.1-Codex: —

BenchmarkGLM-5.3-FlashGPT-5.1-Codex
LMArena Instruction Following1478—

Long Context Not comparable

GLM-5.3-Flash: 45.4 (#39), GPT-5.1-Codex: —

BenchmarkGLM-5.3-FlashGPT-5.1-Codex
LMArena Longer Query1482—

Writing & Preference Not comparable

GLM-5.3-Flash: 65.3 (#50), GPT-5.1-Codex: —

BenchmarkGLM-5.3-FlashGPT-5.1-Codex
LMArena Text1471—
LMArena Creative Writing1442—
LMArena Multi-Turn1467—

Frequently asked questions

Is GLM-5.3-Flash better than GPT-5.1-Codex?

GLM-5.3-Flash is the stronger model overall, scoring 51.8 to 38.6 on the Noometry Index.

Which is cheaper, GLM-5.3-Flash or GPT-5.1-Codex?

GLM-5.3-Flash is cheaper. It lists at $0.15 per million input tokens and $0.50 per million output tokens; GPT-5.1-Codex lists at $1.25 and $10.

Is GLM-5.3-Flash or GPT-5.1-Codex better for coding?

GLM-5.3-Flash scores higher on coding benchmarks: 53.1 versus 41.9 in the Noometry coding category.

Which has the bigger context window?

GLM-5.3-Flash does, with 1M tokens against 400K.

How many benchmarks do GLM-5.3-Flash and GPT-5.1-Codex share?

3 benchmarks have published results for both models. GLM-5.3-Flash has 40 scored results on Noometry and GPT-5.1-Codex has 6.

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