GPT-5.5 Instant vs Grok 4.6
GPT-5.5 Instant 
Grok 4.6 Verdict
- Grok 4.6 (medium) leads on quality: 63.9 vs 60.5.
- GPT-5.5 Instant is stronger in agents & tools, human preference, instruction following, maths, multimodal, reasoning.
- Grok 4.6 (medium) is stronger in coding, composite, knowledge, long context.
- Grok 4.6 (medium) is 3.8× cheaper ($3.00 vs $11.25 per 1M blended).
- GPT-5.5 Instant streams 2.4× faster (129 vs 53 tokens per second).
| Metric | GPT-5.5 Instant | Grok 4.6 (medium) |
|---|---|---|
| BenchLeader Index | 60.5 | 63.9 |
| Agents & tools score | 70.7 | – |
| Coding score | 61.1 | 64.1 |
| Composite score | 62.9 | 83.4 |
| Human preference score | 67.5 | – |
| Instruction following score | 69.8 | – |
| Knowledge score | 69.4 | 77.5 |
| Long context score | 61.4 | 67.1 |
| Maths score | 42.5 | – |
| Multimodal score | 59.7 | – |
| Reasoning score | 62.6 | 62.1 |
| Blended price $/M | $11.25 | $3.00 |
| Output speed | 129 tok/s | 53 tok/s |
| Time to first answer | 16.8 s | 33.4 s |
| Context window | 400k | 500k |
| GPQA Diamond | 82.5% | – |
| FrontierMath Tiers 1–3 | 26.3% | – |
| FrontierMath Tier 4 | 2.4% | – |
| OTIS Mock AIME | 68.1% | – |
| SciCode | 48.6% | 54.6% |
| Epoch Capabilities Index | 142.5 | – |
| LMArena Text | 1474 | – |
| LMArena Hard Prompts | 1491 | – |
| LMArena Coding | 1514 | – |
| LMArena Vision | 1251 | – |
| AA Intelligence Index | 26.8 | 43.0 |
| IFBench | 71.5% | – |
| AA-LCR | 70.0% | 81.0% |
| AA-Omniscience | 11.2 | 28 |
| Terminal-Bench Hard | 42.4% | – |
| GPQA Diamond (AA) | 84.7% | 93.5% |
| Humanity's Last Exam (AA) | 21.6% | 42.1% |
| SciCode (AA) | 52.5% | 55.9% |
| τ²-Bench Telecom (AA) | 49.4% | – |
| ARC-AGI-1 | – | 87.5% |
| ARC-AGI-2 | – | 61.3% |
Data as of 2026-09-10. Best configuration of each model; every score links to its source on the model pages.
GPT-5.5 Instant vs Grok 4.6: questions
- Is GPT-5.5 Instant better than Grok 4.6?
- Grok 4.6 (medium) leads on quality: 63.9 vs 60.5. The BenchLeader Index combines every independent quality benchmark; Grok 4.6 (medium) is ahead overall as of 2026-09-10, but check the category scores for your use.
- Is GPT-5.5 Instant better than Grok 4.6 for coding?
- Grok 4.6 scores higher in coding (64 vs 61 on the category index, where 50 is average).
- Which is cheaper, GPT-5.5 Instant or Grok 4.6?
- Grok 4.6 is cheaper: $3.00 against $11.25 per million tokens, blended at three input tokens per output token.
- Which is faster, GPT-5.5 Instant or Grok 4.6?
- GPT-5.5 Instant streams faster: 129 against 53 output tokens per second.
- Which has the larger context window?
- Grok 4.6 accepts more context: 500k against 400k tokens.