Noometry

Model comparison

GPT-5.1-Codex vs Muse Spark 1.2

Muse Spark 1.2 is the stronger model overall, scoring 50.3 to 38.6 on the Noometry Index.

Last verified . 2 shared benchmarks.

GPT-5.1-Codex OpenAI

38.6

Rank #186 Reported

Muse Spark 1.2 Meta

50.3

Rank #48 Confirmed

Summary

  • They share 2 benchmarks with published results for both. GPT-5.1-Codex scores higher in 1 category and Muse Spark 1.2 in 2 categories; 3 gaps are clear of the uncertainty.
  • The widest gap is in math, where Muse Spark 1.2 leads 46.4 to 30.3.
  • The biggest single-benchmark swing is ProofBench: 9% for GPT-5.1-Codex and 43% for Muse Spark 1.2.
  • Muse Spark 1.2 is cheaper at $1.25 / $4.25 per million input/output tokens, against $1.25 / $10 for GPT-5.1-Codex.
  • Muse Spark 1.2 accepts more context: 1.05M tokens versus 400K.

Side by side

GPT-5.1-CodexMuse Spark 1.2
ProviderOpenAIMeta
Noometry Index38.650.3
Released2025-11-122026-08-05
WeightsProprietaryProprietary
Context window400K1.05M
Max output128K131K
Input $ / M tokens$1.25$1.25
Output $ / M tokens$10$4.25
Results tracked631

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Category by category

Coding Muse Spark 1.2 leads

GPT-5.1-Codex: 41.9 (#116), Muse Spark 1.2: 49.2 (#51)

BenchmarkGPT-5.1-CodexMuse Spark 1.2
LMArena WebDev13371533
DeepSWE—54.9%
SWE-bench Verified (bash only)66%—
FrontierSWE—12%
SciCode—56.4%
WeirdML—60.3%
LMArena Coding—1495
ALE-Bench1,245—

Agentic & Tool Use GPT-5.1-Codex leads

GPT-5.1-Codex: 38.0 (#33), Muse Spark 1.2: 29.4 (#87)

BenchmarkGPT-5.1-CodexMuse Spark 1.2
Terminal-Bench60.4%—
APEX-Agents—36.4%
GDP.pdf—16%
METR Time Horizons70.8%—

Reasoning Not comparable

GPT-5.1-Codex: —, Muse Spark 1.2: 51.3 (#34)

BenchmarkGPT-5.1-CodexMuse Spark 1.2
SimpleBench—74.5%
NYT Connections (extended)—79.2%
CritPt—17.7%
LMArena Hard Prompts—1486
DTBench—94.7%
LMCA—48.4%
Epoch Capabilities Index—154.87

Math Muse Spark 1.2 leads

GPT-5.1-Codex: 30.3 (#235), Muse Spark 1.2: 46.4 (#70)

BenchmarkGPT-5.1-CodexMuse Spark 1.2
ProofBench9%43%
LMArena Math—1471

Knowledge Not comparable

GPT-5.1-Codex: —, Muse Spark 1.2: 54.1 (#53)

BenchmarkGPT-5.1-CodexMuse Spark 1.2
SimpleQA Verified—60.3%
LMArena Expert—1480

Multimodal Not comparable

GPT-5.1-Codex: —, Muse Spark 1.2: 43.4 (#25)

BenchmarkGPT-5.1-CodexMuse Spark 1.2
LMArena Vision—1305

Multilingual Not comparable

GPT-5.1-Codex: —, Muse Spark 1.2: 57.1 (#11)

BenchmarkGPT-5.1-CodexMuse Spark 1.2
LMArena Non-English—1478
LMArena Chinese—1511
LMArena French—1513
LMArena Russian—1487
LMArena Spanish—1498

Instruction Following Not comparable

GPT-5.1-Codex: —, Muse Spark 1.2: 76.7 (#36)

BenchmarkGPT-5.1-CodexMuse Spark 1.2
LMArena Instruction Following—1461

Long Context Not comparable

GPT-5.1-Codex: —, Muse Spark 1.2: 45.2 (#48)

BenchmarkGPT-5.1-CodexMuse Spark 1.2
LMArena Longer Query—1475

Writing & Preference Not comparable

GPT-5.1-Codex: —, Muse Spark 1.2: 72.3 (#14)

BenchmarkGPT-5.1-CodexMuse Spark 1.2
LMArena Text—1482
LMArena Creative Writing—1449
EQ-Bench Creative Writing—1840
LMArena Multi-Turn—1494

Frequently asked questions

Is GPT-5.1-Codex better than Muse Spark 1.2?

Muse Spark 1.2 is the stronger model overall, scoring 50.3 to 38.6 on the Noometry Index.

Which is cheaper, GPT-5.1-Codex or Muse Spark 1.2?

Muse Spark 1.2 is cheaper. It lists at $1.25 per million input tokens and $4.25 per million output tokens; GPT-5.1-Codex lists at $1.25 and $10.

Is GPT-5.1-Codex or Muse Spark 1.2 better for coding?

Muse Spark 1.2 scores higher on coding benchmarks: 49.2 versus 41.9 in the Noometry coding category.

Which has the bigger context window?

Muse Spark 1.2 does, with 1.05M tokens against 400K.

How many benchmarks do GPT-5.1-Codex and Muse Spark 1.2 share?

2 benchmarks have published results for both models. GPT-5.1-Codex has 6 scored results on Noometry and Muse Spark 1.2 has 31.

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