Noometry

Model comparison

GPT-5-Codex vs Muse Spark 1.2

Muse Spark 1.2 is the stronger model overall, scoring 50.3 to 37.9 on the Noometry Index.

Last verified . 1 shared benchmarks.

GPT-5-Codex OpenAI

37.9

Rank #192 Reported

Muse Spark 1.2 Meta

50.3

Rank #48 Confirmed

Summary

  • They share 1 benchmark with published results for both. GPT-5-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 reasoning, where Muse Spark 1.2 leads 51.3 to 30.9.
  • The biggest single-benchmark swing is WeirdML: 54.5% for GPT-5-Codex and 60.3% 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-Codex.
  • Muse Spark 1.2 accepts more context: 1.05M tokens versus 400K.

Side by side

GPT-5-CodexMuse Spark 1.2
ProviderOpenAIMeta
Noometry Index37.950.3
Released2025-09-152026-08-05
WeightsProprietaryProprietary
Context window400K1.05M
Max output128K131K
Input $ / M tokens$1.25$1.25
Output $ / M tokens$10$4.25
Results tracked331

Sponsored placements are available on pages like this one. Advertise on Noometry

Category by category

Coding Muse Spark 1.2 leads

GPT-5-Codex: 42.4 (#103), Muse Spark 1.2: 49.2 (#51)

BenchmarkGPT-5-CodexMuse Spark 1.2
WeirdML54.5%60.3%
DeepSWE—54.9%
LMArena WebDev—1533
FrontierSWE—12%
SciCode—56.4%
LMArena Coding—1495

Agentic & Tool Use GPT-5-Codex leads

GPT-5-Codex: 31.0 (#72), Muse Spark 1.2: 29.4 (#87)

BenchmarkGPT-5-CodexMuse Spark 1.2
Terminal-Bench44.3%—
APEX-Agents—36.4%
GDP.pdf—16%

Reasoning Muse Spark 1.2 leads

GPT-5-Codex: 30.9 (#83), Muse Spark 1.2: 51.3 (#34)

BenchmarkGPT-5-CodexMuse Spark 1.2
SimpleBench—74.5%
Kagi LLM Benchmark70.3%—
NYT Connections (extended)—79.2%
CritPt—17.7%
LMArena Hard Prompts—1486
DTBench—94.7%
LMCA—48.4%
Epoch Capabilities Index—154.87

Math Not comparable

GPT-5-Codex: —, Muse Spark 1.2: 46.4 (#70)

BenchmarkGPT-5-CodexMuse Spark 1.2
ProofBench—43%
LMArena Math—1471

Knowledge Not comparable

GPT-5-Codex: —, Muse Spark 1.2: 54.1 (#53)

BenchmarkGPT-5-CodexMuse Spark 1.2
SimpleQA Verified—60.3%
LMArena Expert—1480

Multimodal Not comparable

GPT-5-Codex: —, Muse Spark 1.2: 43.4 (#25)

BenchmarkGPT-5-CodexMuse Spark 1.2
LMArena Vision—1305

Multilingual Not comparable

GPT-5-Codex: —, Muse Spark 1.2: 57.1 (#11)

BenchmarkGPT-5-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-Codex: —, Muse Spark 1.2: 76.7 (#36)

BenchmarkGPT-5-CodexMuse Spark 1.2
LMArena Instruction Following—1461

Long Context Not comparable

GPT-5-Codex: —, Muse Spark 1.2: 45.2 (#48)

BenchmarkGPT-5-CodexMuse Spark 1.2
LMArena Longer Query—1475

Writing & Preference Not comparable

GPT-5-Codex: —, Muse Spark 1.2: 72.3 (#14)

BenchmarkGPT-5-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-Codex better than Muse Spark 1.2?

Muse Spark 1.2 is the stronger model overall, scoring 50.3 to 37.9 on the Noometry Index.

Which is cheaper, GPT-5-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-Codex lists at $1.25 and $10.

Is GPT-5-Codex or Muse Spark 1.2 better for coding?

Muse Spark 1.2 scores higher on coding benchmarks: 49.2 versus 42.4 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-Codex and Muse Spark 1.2 share?

1 benchmark has published results for both models. GPT-5-Codex has 3 scored results on Noometry and Muse Spark 1.2 has 31.

Related comparisons

Go deeper