Gemini 3.1 Pro vs GPT-5.6 Terra
Gemini 3.1 Pro 
GPT-5.6 Terra Verdict
- Gemini 3.1 Pro and GPT-5.6 Terra (xhigh) are level on quality (63.9 vs 64.2).
- Gemini 3.1 Pro is stronger in instruction following, knowledge, long context, multimodal, reasoning.
- GPT-5.6 Terra (xhigh) is stronger in agents & tools, coding, composite, human preference, maths.
- They cost about the same ($4.50 per 1M blended).
| Metric | Gemini 3.1 Pro | GPT-5.6 Terra (xhigh) |
|---|---|---|
| BenchLeader Index | 63.9 | 64.2 |
| Agents & tools score | 63.7 | 69.6 |
| Coding score | 59.8 | 63.7 |
| Composite score | 67.2 | 77.1 |
| Human preference score | 59.6 | 66.3 |
| Instruction following score | 69.5 | 65.0 |
| Knowledge score | 66.1 | 60.9 |
| Long context score | 67.6 | 66.0 |
| Maths score | 60.7 | 71.0 |
| Multimodal score | 66.1 | 63.0 |
| Reasoning score | 69.5 | 58.2 |
| Blended price $/M | $4.50 | $4.50 |
| Output speed | 110 tok/s | 93 tok/s |
| Time to first answer | 30.5 s | 32.5 s |
| Context window | 1.0M | 1M |
| GPQA Diamond | 94.1% | – |
| FrontierMath Tiers 1–3 | 59.6% | – |
| FrontierMath Tier 4 | 26.8% | – |
| OTIS Mock AIME | 95.6% | – |
| Humanity's Last Exam | 46.4% | – |
| Terminal-Bench | 80.2% | – |
| SimpleBench | 79.6% | 48.9% |
| SciCode | 58.9% | 51.6% |
| WeirdML | 72.1% | – |
| APEX-Agents | 33.5% | – |
| ProofBench | 26.0% | 74.0% |
| GSO-Bench | 22.6% | – |
| Epoch Capabilities Index | 155 | – |
| LMArena Text | 1487 | 1466 |
| LMArena Hard Prompts | 1507 | 1491 |
| LMArena Coding | 1521 | 1519 |
| LMArena WebDev | 1447 | 1521 |
| LMArena Vision | 1295 | 1269 |
| LMArena Agent | -5.3 | 1.5 |
| AA Intelligence Index | 30.4 | 38.2 |
| IFBench | 77.1% | 66.3% |
| AA-LCR | 82.0% | 79.0% |
| MMMU-Pro | 82.4% | 79.5% |
| AA-Omniscience | 31.9 | -3.0 |
| Terminal-Bench Hard | 53.8% | 62.9% |
| GPQA Diamond (AA) | 94.1% | 90.8% |
| Humanity's Last Exam (AA) | 47.0% | 41.9% |
| SciCode (AA) | 58.7% | 52.3% |
| τ²-Bench Telecom (AA) | 95.6% | 80.4% |
| LiveCodeBench | – | 85.9% |
| MMLU-Pro | – | 86.7% |
| IOI | – | 65.3% |
| CorpFin | – | 65.3% |
| TaxEval | – | 76.2% |
| GPQA Diamond (Vals) | – | 90.9% |
| AIME 2026 | 98.3% | – |
| HMMT February 2026 | 94.7% | – |
| MathArena Apex | 60.9% | – |
| MultiChallenge | 71.4% | – |
| PRBench Finance | 41.9% | – |
| PRBench Legal | 44.0% | – |
| MultiNRC | 64.7% | – |
| HiL-Bench | 35.3% | – |
| TutorBench | 53.0% | – |
| EQ-Bench 4 | 1142 | – |
| ARC-AGI-1 | 98.0% | 94.0% |
| ARC-AGI-2 | 77.1% | 74.2% |
| ARC-AGI-3 | 0.4% | 0.7% |
Data as of 2026-09-09. Best configuration of each model; every score links to its source on the model pages.