Model comparison
GPT-5.3 Codex vs Muse Spark
Muse Spark is the stronger model overall, scoring 50.6 to 45.8 on the Noometry Index.
Last verified . 1 shared benchmarks.
MetaSummary
- They share 1 benchmark with published results for both. GPT-5.3 Codex scores higher in 1 category and Muse Spark in 0 categories; one gap is clear of the uncertainty.
Side by side
| GPT-5.3 Codex | Muse Spark | |
|---|---|---|
| Provider | OpenAI | Meta |
| Noometry Index | 45.8 | 50.6 |
| Released | 2026-02-05 | 2026-04-08 |
| Weights | Proprietary | Proprietary |
| Context window | 400K | — |
| Max output | 128K | — |
| Input $ / M tokens | $1.75 | — |
| Output $ / M tokens | $14 | — |
| Results tracked | 8 | 27 |
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Category by category
Coding GPT-5.3 Codex leads
GPT-5.3 Codex: 48.6 (#56), Muse Spark: 46.2 (#69)
| Benchmark | GPT-5.3 Codex | Muse Spark |
|---|---|---|
| SWE-bench Verified | 74.8% | — |
| LMArena WebDev | 1409 | — |
| SciCode | — | 51.5% |
| WeirdML | 79.3% | — |
| LMArena Coding | — | 1481 |
| ALE-Bench | 1,655 | — |
Agentic & Tool Use Not comparable
GPT-5.3 Codex: 48.0 (#9), Muse Spark: —
| Benchmark | GPT-5.3 Codex | Muse Spark |
|---|---|---|
| Terminal-Bench | 78.4% | — |
| METR Time Horizons | 74.5% | — |
| Vending-Bench 2 | 5,940 | — |
Reasoning Not comparable
GPT-5.3 Codex: —, Muse Spark: 35.9 (#67)
| Benchmark | GPT-5.3 Codex | Muse Spark |
|---|---|---|
| Epoch Capabilities Index | 156.77 | 152.04 |
| CritPt | — | 11.3% |
| LMArena Hard Prompts | — | 1474 |
Math Not comparable
GPT-5.3 Codex: —, Muse Spark: 47.8 (#66)
| Benchmark | GPT-5.3 Codex | Muse Spark |
|---|---|---|
| OTIS Mock AIME 2024-2025 | — | 88.9% |
| ProofBench | — | 17% |
| LMArena Math | — | 1455 |
| FrontierMath (Feb 2025 set) | — | 39% |
| FrontierMath Tier 4 (v1) | — | 14.6% |
Knowledge Not comparable
GPT-5.3 Codex: —, Muse Spark: 65.7 (#13)
| Benchmark | GPT-5.3 Codex | Muse Spark |
|---|---|---|
| GPQA Diamond | — | 89.8% |
| Humanity's Last Exam | — | 40.6% |
| LMArena Expert | — | 1457 |
Multimodal Not comparable
GPT-5.3 Codex: —, Muse Spark: 43.4 (#24)
| Benchmark | GPT-5.3 Codex | Muse Spark |
|---|---|---|
| LMArena Vision | — | 1306 |
| LMArena Document | — | 1444 |
Multilingual Not comparable
GPT-5.3 Codex: —, Muse Spark: 56.1 (#24)
| Benchmark | GPT-5.3 Codex | Muse Spark |
|---|---|---|
| LMArena Non-English | — | 1464 |
| LMArena Chinese | — | 1509 |
| LMArena French | — | 1497 |
| LMArena German | — | 1497 |
| LMArena Korean | — | 1459 |
| LMArena Russian | — | 1466 |
| LMArena Spanish | — | 1472 |
Instruction Following Not comparable
GPT-5.3 Codex: —, Muse Spark: 75.9 (#51)
| Benchmark | GPT-5.3 Codex | Muse Spark |
|---|---|---|
| LMArena Instruction Following | — | 1442 |
Long Context Not comparable
GPT-5.3 Codex: —, Muse Spark: 44.4 (#69)
| Benchmark | GPT-5.3 Codex | Muse Spark |
|---|---|---|
| LMArena Longer Query | — | 1451 |
Writing & Preference Not comparable
GPT-5.3 Codex: —, Muse Spark: 66.0 (#39)
| Benchmark | GPT-5.3 Codex | Muse Spark |
|---|---|---|
| LMArena Text | — | 1474 |
| LMArena Creative Writing | — | 1459 |
| LMArena Multi-Turn | — | 1477 |
Frequently asked questions
Is GPT-5.3 Codex better than Muse Spark?
Muse Spark is the stronger model overall, scoring 50.6 to 45.8 on the Noometry Index.
Is GPT-5.3 Codex or Muse Spark better for coding?
GPT-5.3 Codex scores higher on coding benchmarks: 48.6 versus 46.2 in the Noometry coding category.
How many benchmarks do GPT-5.3 Codex and Muse Spark share?
1 benchmark has published results for both models. GPT-5.3 Codex has 8 scored results on Noometry and Muse Spark has 27.