# GPT-5.1-Codex vs Muse Spark 1.3

> Muse Spark 1.3 is the stronger model overall, scoring 54.4 to 38.2 on the Noometry Index.

- Canonical page: https://noometry.com/compare/gpt-5-1-codex-vs-muse-spark-1-3
- Last updated: 2026-10-10
- Shared benchmarks: 1

## Summary

- They share 1 benchmark with published results for both. GPT-5.1-Codex scores higher in 0 categories and Muse Spark 1.3 in 3 categories; 2 gaps are clear of the uncertainty.
- The widest gap is in math, where Muse Spark 1.3 leads 72.4 to 29.3.
- Muse Spark 1.3 is cheaper at $1.25 / $4.25 per million input/output tokens, against $1.25 / $10 for GPT-5.1-Codex.
- Muse Spark 1.3 accepts more context: 1.05M tokens versus 400K.

## Snapshot

| | GPT-5.1-Codex | Muse Spark 1.3 |
|---|---|---|
| Provider | OpenAI | Meta |
| Noometry Index | 38.2 | 54.4 |
| Rank | 178 | 27 |
| Context | 400K | 1.05M |
| Input $/M | $1.25 | $1.25 |
| Output $/M | $10 | $4.25 |
| Weights | Proprietary | Proprietary |

## Coding

- GPT-5.1-Codex: 41.7 (#107)
- Muse Spark 1.3: 56.1 (#18)

| Benchmark | GPT-5.1-Codex | Muse Spark 1.3 |
|---|---|---|
| LMArena WebDev | 1337 | 1655 |
| SWE-bench Verified (bash only) | 66% | — |
| CursorBench | — | 41.6% |
| SciCode | — | 59.7% |
| LMArena Coding | — | 1516 |
| ALE-Bench | 1,245 | — |

## Agentic & Tool Use

- GPT-5.1-Codex: 37.8 (#32)
- Muse Spark 1.3: 38.6 (#28)

| Benchmark | GPT-5.1-Codex | Muse Spark 1.3 |
|---|---|---|
| Terminal-Bench | 60.4% | — |
| APEX-Agents | — | 57.8% |
| GDP.pdf | — | 27.6% |
| METR Time Horizons | 70.8% | — |

## Reasoning

- GPT-5.1-Codex: —
- Muse Spark 1.3: 52.9 (#27)

| Benchmark | GPT-5.1-Codex | Muse Spark 1.3 |
|---|---|---|
| NYT Connections (extended) | — | 85.1% |
| CritPt | — | 24.9% |
| Chess Puzzles | — | 38% |
| LMArena Hard Prompts | — | 1503 |
| Mystery Game Puzzles | — | 25% |
| DTBench | — | 96.5% |
| LMCA | — | 53.9% |
| Bench to the Future 3 | — | 0.14 |
| Epoch Capabilities Index | — | 156.89 |

## Math

- GPT-5.1-Codex: 29.3 (#218)
- Muse Spark 1.3: 72.4 (#16)

| Benchmark | GPT-5.1-Codex | Muse Spark 1.3 |
|---|---|---|
| FrontierMath (Tiers 1-3) | — | 74.4% |
| FrontierMath Tier 4 | — | 46.3% |
| OTIS Mock AIME 2024-2025 | — | 99.2% |
| ProofBench | 9% | — |
| LMArena Math | — | 1497 |

## Knowledge

- GPT-5.1-Codex: —
- Muse Spark 1.3: 42.0 (#92)

| Benchmark | GPT-5.1-Codex | Muse Spark 1.3 |
|---|---|---|
| LMArena Expert | — | 1516 |

## Multimodal

- GPT-5.1-Codex: —
- Muse Spark 1.3: 43.0 (#21)

| Benchmark | GPT-5.1-Codex | Muse Spark 1.3 |
|---|---|---|
| LMArena Vision | — | 1310 |
| LMArena Document | — | 1471 |

## Multilingual

- GPT-5.1-Codex: —
- Muse Spark 1.3: 57.8 (#6)

| Benchmark | GPT-5.1-Codex | Muse Spark 1.3 |
|---|---|---|
| LMArena Non-English | — | 1485 |
| LMArena Chinese | — | 1527 |
| LMArena French | — | 1534 |
| LMArena Korean | — | 1513 |
| LMArena Russian | — | 1491 |
| LMArena Spanish | — | 1485 |

## Instruction Following

- GPT-5.1-Codex: —
- Muse Spark 1.3: 77.8 (#14)

| Benchmark | GPT-5.1-Codex | Muse Spark 1.3 |
|---|---|---|
| LMArena Instruction Following | — | 1481 |

## Long Context

- GPT-5.1-Codex: —
- Muse Spark 1.3: 45.7 (#29)

| Benchmark | GPT-5.1-Codex | Muse Spark 1.3 |
|---|---|---|
| LMArena Longer Query | — | 1491 |

## Writing & Preference

- GPT-5.1-Codex: —
- Muse Spark 1.3: 73.7 (#10)

| Benchmark | GPT-5.1-Codex | Muse Spark 1.3 |
|---|---|---|
| LMArena Text | — | 1490 |
| LMArena Creative Writing | — | 1450 |
| EQ-Bench Creative Writing | — | 1906 |
| LMArena Multi-Turn | — | 1486 |

## FAQ

### Is GPT-5.1-Codex better than Muse Spark 1.3?

Muse Spark 1.3 is the stronger model overall, scoring 54.4 to 38.2 on the Noometry Index.

### Which is cheaper, GPT-5.1-Codex or Muse Spark 1.3?

Muse Spark 1.3 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 1.3 better for coding?

Muse Spark 1.3 scores higher on coding benchmarks: 56.1 versus 41.7 in the Noometry coding category.

### Which has the bigger context window?

Muse Spark 1.3 does, with 1.05M tokens against 400K.

### How many benchmarks do GPT-5.1-Codex and Muse Spark 1.3 share?

1 benchmark has published results for both models. GPT-5.1-Codex has 6 scored results on Noometry and Muse Spark 1.3 has 34.