GPT-5.6 Sol vs GPT-5-Codex
GPT-5.6 Sol Verdict
- GPT-5.6 Sol (high) leads on quality: 68.2 vs 58.2.
- GPT-5.6 Sol (high) is stronger in agents & tools, coding, composite, knowledge, long context, multimodal.
- GPT-5-Codex is stronger in instruction following, reasoning.
- GPT-5-Codex is 2.3× cheaper ($3.44 vs $8.00 per 1M blended).
| Metric | GPT-5.6 Sol (high) | GPT-5-Codex |
|---|---|---|
| BenchLeader Index | 68.2 | 58.2 |
| Agents & tools score | 87.9 | 56.3 |
| Coding score | 72.4 | 53.6 |
| Composite score | 82.7 | 60.4 |
| Instruction following score | 67.8 | 72.1 |
| Knowledge score | 73.8 | 60.6 |
| Long context score | 67.4 | 62.2 |
| Multimodal score | 66.4 | 58.2 |
| Reasoning score | 63.3 | 64.3 |
| Blended price $/M | $8.00 | $3.44 |
| Output speed | 59 tok/s | – |
| Time to first answer | 31.0 s | – |
| Context window | 1M | 400k |
| Terminal-Bench | – | 44.3% |
| SciCode | 56.9% | – |
| WeirdML | 88.8% | 54.5% |
| AA Intelligence Index | 42.5 | 24.9 |
| IFBench | 69.2% | 74.2% |
| AA-LCR | 81.7% | 71.7% |
| MMMU-Pro | 81.8% | 73.8% |
| AA-Omniscience | 20.4 | -7.5 |
| Terminal-Bench Hard | 62.1% | 37.9% |
| GPQA Diamond (AA) | 92.8% | 83.7% |
| Humanity's Last Exam (AA) | 46.0% | 27.9% |
| SciCode (AA) | 57.8% | – |
| τ²-Bench Telecom (AA) | 83.3% | 86.8% |
| EnigmaEval | 37.1% | – |
| Kagi LLM Benchmark | – | 70.3% |
| ARC-AGI-1 | 97.0% | – |
| ARC-AGI-2 | 85.4% | – |
| ARC-AGI-3 | 2.2% | – |
Data as of 2026-09-10. Best configuration of each model; every score links to its source on the model pages.
GPT-5.6 Sol vs GPT-5-Codex: questions
- Is GPT-5.6 Sol better than GPT-5-Codex?
- GPT-5.6 Sol (high) leads on quality: 68.2 vs 58.2. The BenchLeader Index combines every independent quality benchmark; GPT-5.6 Sol (high) is ahead overall as of 2026-09-10, but check the category scores for your use.
- Is GPT-5.6 Sol better than GPT-5-Codex for coding?
- GPT-5.6 Sol scores higher in coding (72 vs 54 on the category index, where 50 is average).
- Is GPT-5.6 Sol better than GPT-5-Codex for agentic tasks?
- GPT-5.6 Sol scores higher in agentic tasks (88 vs 56 on the category index, where 50 is average).
- Which is cheaper, GPT-5.6 Sol or GPT-5-Codex?
- GPT-5-Codex is cheaper: $3.44 against $8.00 per million tokens, blended at three input tokens per output token.
- Which has the larger context window?
- GPT-5.6 Sol accepts more context: 1M against 400k tokens.