GPT-5.6 Terra vs Grok 4.3
GPT-5.6 Terra 
Grok 4.3 Verdict
- GPT-5.6 Terra (xhigh) leads on quality: 64.4 vs 60.7.
- GPT-5.6 Terra (xhigh) is stronger in agents & tools, coding, composite, human preference, long context, maths, multimodal, reasoning.
- Grok 4.3 (medium) is stronger in instruction following, knowledge.
- Grok 4.3 (medium) is 2.9× cheaper ($1.56 vs $4.50 per 1M blended).
- Grok 4.3 (medium) streams 1.4× faster (112 vs 79 tokens per second).
| Metric | GPT-5.6 Terra (xhigh) | Grok 4.3 (medium) |
|---|---|---|
| BenchLeader Index | 64.4 | 60.7 |
| Agents & tools score | 69.8 | 60.1 |
| Coding score | 63.7 | – |
| Composite score | 77.3 | 60.3 |
| Human preference score | 66.7 | – |
| Instruction following score | 65.3 | 80.0 |
| Knowledge score | 61.0 | 72.1 |
| Long context score | 66.0 | 64.0 |
| Maths score | 71.0 | – |
| Multimodal score | 63.0 | 60.2 |
| Reasoning score | 58.6 | – |
| Blended price $/M | $4.50 | $1.56 |
| Output speed | 79 tok/s | 112 tok/s |
| Time to first answer | 33.6 s | 12.1 s |
| Context window | 1M | 1M |
| SimpleBench | 48.9% | – |
| SciCode | 51.6% | – |
| ProofBench | 74.0% | – |
| LMArena Text | 1466 | – |
| LMArena Hard Prompts | 1491 | – |
| LMArena Coding | 1519 | – |
| LMArena WebDev | 1521 | – |
| LMArena Vision | 1269 | – |
| LMArena Agent | 1.5 | – |
| AA Intelligence Index | 38.2 | 24.8 |
| IFBench | 66.3% | 83.3% |
| AA-LCR | 79.0% | 75.0% |
| MMMU-Pro | 79.5% | 75.8% |
| AA-Omniscience | -3.0 | 16.7 |
| Terminal-Bench Hard | 62.9% | 30.3% |
| GPQA Diamond (AA) | 90.8% | 89.0% |
| Humanity's Last Exam (AA) | 41.9% | 30.0% |
| SciCode (AA) | 52.3% | – |
| τ²-Bench Telecom (AA) | 80.4% | 91.2% |
| LiveCodeBench | 85.9% | – |
| MMLU-Pro | 86.7% | – |
| IOI | 65.3% | – |
| CorpFin | 65.3% | – |
| TaxEval | 76.2% | – |
| GPQA Diamond (Vals) | 90.9% | – |
| ARC-AGI-1 | 94.0% | – |
| ARC-AGI-2 | 74.2% | – |
| ARC-AGI-3 | 0.7% | – |
Data as of 2026-09-10. Best configuration of each model; every score links to its source on the model pages.
GPT-5.6 Terra vs Grok 4.3: questions
- Is GPT-5.6 Terra better than Grok 4.3?
- GPT-5.6 Terra (xhigh) leads on quality: 64.4 vs 60.7. The BenchLeader Index combines every independent quality benchmark; GPT-5.6 Terra (xhigh) is ahead overall as of 2026-09-10, but check the category scores for your use.
- Is GPT-5.6 Terra better than Grok 4.3 for agentic tasks?
- GPT-5.6 Terra scores higher in agentic tasks (70 vs 60 on the category index, where 50 is average).
- Which is cheaper, GPT-5.6 Terra or Grok 4.3?
- Grok 4.3 is cheaper: $1.56 against $4.50 per million tokens, blended at three input tokens per output token.
- Which is faster, GPT-5.6 Terra or Grok 4.3?
- Grok 4.3 streams faster: 112 against 79 output tokens per second.
- Which has the larger context window?
- Both accept 1M tokens of context.