GPT-5.6 Sol vs Grok 4.20
GPT-5.6 Sol 
Grok 4.20 Verdict
- GPT-5.6 Sol (max) leads on quality: 68.8 vs 59.9.
- GPT-5.6 Sol (max) is stronger in agents & tools, coding, composite, knowledge, long context, maths, multimodal, reasoning.
- Grok 4.20 (thinking) is stronger in instruction following, human preference.
- Grok 4.20 (thinking) is 5.1× cheaper ($1.56 vs $8.00 per 1M blended).
- Grok 4.20 (thinking) streams 1.7× faster (101 vs 61 tokens per second).
| Metric | GPT-5.6 Sol (max) | Grok 4.20 (thinking) |
|---|---|---|
| BenchLeader Index | 68.8 | 59.9 |
| Agents & tools score | 66.6 | 51.7 |
| Coding score | 67.0 | 54.7 |
| Composite score | 79.2 | 61.5 |
| Instruction following score | 71.0 | 79.9 |
| Knowledge score | 66.5 | 56.8 |
| Long context score | 68.5 | 60.7 |
| Maths score | 74.3 | 55.6 |
| Multimodal score | 68.1 | 59.9 |
| Reasoning score | 73.7 | 60.7 |
| Human preference score | – | 67.1 |
| Blended price $/M | $8.00 | $1.56 |
| Output speed | 61 tok/s | 101 tok/s |
| Time to first answer | 127.3 s | 21.4 s |
| Context window | 1.1M | 1M |
| GPQA Diamond | 93.5% | 89.3% |
| FrontierMath Tiers 1–3 | 89.1% | 44.9% |
| FrontierMath Tier 4 | 82.9% | 17.1% |
| OTIS Mock AIME | 100.0% | 92.2% |
| SimpleQA Verified | 69.7% | 30.2% |
| Terminal-Bench | 37.3% | – |
| OSWorld-Verified 2.0 | 27.3% | – |
| SciCode | 56.1% | – |
| WeirdML | 87.0% | – |
| APEX-Agents | 39.9% | – |
| ProofBench | 83.0% | 14.0% |
| LMArena Text | – | 1472 |
| LMArena Hard Prompts | – | 1488 |
| LMArena Coding | – | 1510 |
| LMArena WebDev | – | 1374 |
| LMArena Vision | – | 1263 |
| LiveBench | 81.0% | – |
| LiveBench Reasoning | 91.7% | – |
| LiveBench Coding | 83.9% | – |
| LiveBench Agentic Coding | 56.2% | – |
| LiveBench Mathematics | 96.2% | – |
| LiveBench Data Analysis | 79.8% | – |
| LiveBench Language | 87.7% | – |
| LiveBench Instruction Following | 71.8% | – |
| AA Intelligence Index | 47.1 | 25.7 |
| IFBench | 72.7% | 82.9% |
| AA-LCR | 84.0% | 69.0% |
| MMMU-Pro | 83.4% | 74.6% |
| AA-Omniscience | 22.0 | 14.8 |
| Terminal-Bench Hard | 65.9% | 40.9% |
| GPQA Diamond (AA) | 94.1% | 91.1% |
| Humanity's Last Exam (AA) | 49.5% | 34.5% |
| SciCode (AA) | 57.1% | – |
| τ²-Bench Telecom (AA) | 85.1% | 96.5% |
| AIME (Vals) | – | 96.5% |
| LiveCodeBench | 82.6% | 84.3% |
| MMLU-Pro | 89.1% | 86.3% |
| IOI | 91.2% | – |
| LegalBench | 87.0% | 77.7% |
| CorpFin | 64.4% | 63.7% |
| TaxEval | 74.8% | 74.1% |
| MedQA | – | 94.5% |
| Terminal-Bench 2.1 (Vals) | 85.8% | 44.2% |
| SWE-bench (Vals) | 96.2% | 72.2% |
| GPQA Diamond (Vals) | 95.2% | 88.6% |
| Vals Index | 63.7 | 17.6 |
| PRBench Finance | 50.5% | – |
| PRBench Legal | 50.5% | – |
| Kagi LLM Benchmark | – | 75.0% |
| ARC-AGI-1 | 96.5% | 89.5% |
| ARC-AGI-2 | 92.5% | 65.1% |
| ARC-AGI-3 | 7.8% | 0.1% |
| CritPt | 32.3% | 6.6% |
| GDPval (AA) | 54.3% | – |
| τ²-Bench Banking (AA) | 44.3% | – |
| ITBench SRE (AA) | 56.2% | – |
| Analyst Agent (AA) | 47.5% | – |
| APEX-Agents (AA) | – | 14.2% |
| BioMysteryBench | 71.1% | – |
| CaseLaw v2 | – | 54.5% |
| Code Migration | 52.9% | 0.3% |
| CUA-bench | 8.3% | – |
| Excel Modeling Benchmark | 72.3% | 11.7% |
| Finance Agent v2 | 53.8% | 28.5% |
| Harvey's Legal Agent Benchmark | 2.5% | 0.0% |
| Legal Research Bench | 48.1% | 13.9% |
| MedCode | 44.0% | 32.2% |
| MedScribe | 85.2% | 63.4% |
| MMMU-Pro (Vals) | 88.8% | 83.5% |
| MortgageTax | 67.3% | 45.4% |
| MysteryMechanism | 33.3% | – |
| ProgramBench | 1.5% | – |
| Public Benefits Bench | 66.5% | – |
| SAGE | 52.6% | 38.2% |
| SkillsBench | 54.1% | – |
| SREBench | 30.5% | – |
| Tax Agent Bench | 68.0% | – |
| Terminal-Bench 2.0 (Vals) | – | 40.5% |
| Terminal-Bench 4.0 (Vals) | 27.8% | – |
| Terminal-Bench Science | 12.9% | – |
| Time Horizon Index: KSP | 23.8% | – |
| Vals Multimodal Index | 72.6% | 39.1% |
| Vibe Code Bench 1-100 | 20.0% | – |
| Vibe Code Bench v1.1 | 80.5% | 4.1% |
| Web Search Index | 43.6% | – |
| DrugDiscoveryBench | 56.5% | – |
| LMArena Maths | – | 1467 |
| LMArena Creative Writing | – | 1446 |
| LMArena Instruction Following | – | 1445 |
| LMArena Multi-turn | – | 1480 |
| LMArena Longer Queries | – | 1465 |
| LMArena Document | – | 1439 |
| Chess Puzzles | 55.0% | 24.0% |
| EBR-bench | 44.8% | – |
| Mystery Game Puzzles | 58.0% | – |
| PostTrainBench | 36.2% | – |
| DeepSWE | 72.7% | – |
| LMCA | 58.4% | – |
| DTBench | 95.5% | – |
| ForecastBench | – | 60.7% |
| CursorBench | 67.2% | – |
| ALE-Bench | 2176.9 | – |
| GDP.pdf | 30.7% | – |
| FrontierSWE | 32.2% | – |
| BTF-3 | 13.7% | – |
Data as of 2026-09-19. Best configuration of each model; every score links to its source on the model pages.
GPT-5.6 Sol vs Grok 4.20: questions
- Is GPT-5.6 Sol better than Grok 4.20?
- GPT-5.6 Sol (max) leads on quality: 68.8 vs 59.9. The BenchLeader Index combines every independent quality benchmark; GPT-5.6 Sol (max) is ahead overall as of 2026-09-19, but check the category scores for your use.
- Is GPT-5.6 Sol better than Grok 4.20 for coding?
- GPT-5.6 Sol scores higher in coding (67 vs 55 on the category index, where 50 is average).
- Is GPT-5.6 Sol better than Grok 4.20 for agentic tasks?
- GPT-5.6 Sol scores higher in agentic tasks (67 vs 52 on the category index, where 50 is average).
- Which is cheaper, GPT-5.6 Sol or Grok 4.20?
- Grok 4.20 is cheaper: $1.56 against $8.00 per million tokens, blended at three input tokens per output token.
- Which is faster, GPT-5.6 Sol or Grok 4.20?
- Grok 4.20 streams faster: 101 against 61 output tokens per second.
- Which has the larger context window?
- GPT-5.6 Sol accepts more context: 1.1M against 1M tokens.