GPT-5.3-Codex vs Muse Spark 1.3
GPT-5.3-Codex 
Muse Spark 1.3 Verdict
- Muse Spark 1.3 (xhigh) leads on quality: 63.9 vs 62.5.
- GPT-5.3-Codex is stronger in agents & tools, instruction following, long context.
- Muse Spark 1.3 (xhigh) is stronger in coding, composite, knowledge, multimodal.
- Muse Spark 1.3 (xhigh) is 2.4× cheaper ($2.00 vs $4.81 per 1M blended).
- Muse Spark 1.3 (xhigh) streams 1.6× faster (190 vs 121 tokens per second).
| Metric | GPT-5.3-Codex | Muse Spark 1.3 (xhigh) |
|---|---|---|
| BenchLeader Index | 62.5 | 63.9 |
| Agents & tools score | 62.7 | 60.2 |
| Coding score | 54.8 | 70.3 |
| Composite score | 70.1 | 78.6 |
| Instruction following score | 73.2 | – |
| Knowledge score | 69.3 | 75.1 |
| Long context score | 68.3 | 68.1 |
| Multimodal score | 63.0 | 66.6 |
| Blended price $/M | $4.81 | $2.00 |
| Output speed | 121 tok/s | 190 tok/s |
| Time to first answer | 58.2 s | 35.7 s |
| Context window | 400k | 1M |
| Terminal-Bench | 78.4% | – |
| WeirdML | 79.3% | – |
| APEX-Agents | 31.8% | – |
| Epoch Capabilities Index | 156.6 | – |
| LMArena WebDev | 1409 | 1625 |
| LiveBench | – | 81.6% |
| LiveBench Reasoning | – | 89.7% |
| LiveBench Coding | – | 81.1% |
| LiveBench Agentic Coding | – | 64.1% |
| LiveBench Mathematics | – | 96.0% |
| LiveBench Data Analysis | – | 79.6% |
| LiveBench Language | – | 82.8% |
| AA Intelligence Index | 32.5 | 45.2 |
| IFBench | 75.4% | – |
| AA-LCR | 83.3% | 83.0% |
| MMMU-Pro | 78.5% | 82.0% |
| AA-Omniscience | 10.9 | 23.1 |
| Terminal-Bench Hard | 53.0% | – |
| GPQA Diamond (AA) | 91.5% | 94.1% |
| Humanity's Last Exam (AA) | 42.5% | 47.5% |
| SciCode (AA) | – | 59.7% |
| τ²-Bench Telecom (AA) | 86.0% | – |
| Terminal-Bench 2.1 (Vals) | – | 72.3% |
| Vals Index | – | 60.3 |
| HiL-Bench | 4.3% | – |
Data as of 2026-09-10. Best configuration of each model; every score links to its source on the model pages.
GPT-5.3-Codex vs Muse Spark 1.3: questions
- Is GPT-5.3-Codex better than Muse Spark 1.3?
- Muse Spark 1.3 (xhigh) leads on quality: 63.9 vs 62.5. The BenchLeader Index combines every independent quality benchmark; Muse Spark 1.3 (xhigh) is ahead overall as of 2026-09-10, but check the category scores for your use.
- Is GPT-5.3-Codex better than Muse Spark 1.3 for coding?
- Muse Spark 1.3 scores higher in coding (70 vs 55 on the category index, where 50 is average).
- Is GPT-5.3-Codex better than Muse Spark 1.3 for agentic tasks?
- GPT-5.3-Codex scores higher in agentic tasks (63 vs 60 on the category index, where 50 is average).
- Which is cheaper, GPT-5.3-Codex or Muse Spark 1.3?
- Muse Spark 1.3 is cheaper: $2.00 against $4.81 per million tokens, blended at three input tokens per output token.
- Which is faster, GPT-5.3-Codex or Muse Spark 1.3?
- Muse Spark 1.3 streams faster: 190 against 121 output tokens per second.
- Which has the larger context window?
- Muse Spark 1.3 accepts more context: 1M against 400k tokens.