GPT-5.5 Pro vs Grok 4.20 Multi-Agent
GPT-5.5 Pro 
Grok 4.20 Multi-Agent Verdict
- GPT-5.5 Pro (xhigh) leads on quality: 67.0 vs 59.2.
- GPT-5.5 Pro (xhigh) is stronger in maths, reasoning.
- Grok 4.20 Multi-Agent is stronger in coding, human preference, multimodal.
- Grok 4.20 Multi-Agent is 43× cheaper ($1.56 vs $67.50 per 1M blended).
- Grok 4.20 Multi-Agent streams 76.0× faster (304 vs 4 tokens per second).
| Metric | GPT-5.5 Pro (xhigh) | Grok 4.20 Multi-Agent |
|---|---|---|
| BenchLeader Index | 67.0 | 59.2 |
| Maths score | 74.4 | 64.4 |
| Reasoning score | 80.1 | 65.9 |
| Coding score | – | 65.5 |
| Human preference score | – | 67.0 |
| Multimodal score | – | 60.4 |
| Blended price $/M | $67.50 | $1.56 |
| Output speed | 4 tok/s | 304 tok/s |
| Time to first answer | 3.5 s | 9.9 s |
| Context window | 1.1M | 1M |
| FrontierMath Tiers 1–3 | 87.7% | – |
| FrontierMath Tier 4 | 78.0% | – |
| LMArena Text | – | 1470 |
| LMArena Hard Prompts | – | 1483 |
| LMArena Coding | – | 1508 |
| LMArena Vision | – | 1260 |
| ARC-AGI-1 | 95.0% | – |
| ARC-AGI-2 | 84.2% | – |
| CritPt | 30.6% | – |
| LMArena Maths | – | 1453 |
| LMArena Creative Writing | – | 1448 |
| LMArena Instruction Following | – | 1443 |
| LMArena Multi-turn | – | 1473 |
| LMArena Longer Queries | – | 1457 |
| LMArena Search | – | 1205 |
| LMCA | 53.9% | – |
| DTBench | 96.0% | – |
Data as of 2026-09-21. Best configuration of each model; every score links to its source on the model pages.
GPT-5.5 Pro vs Grok 4.20 Multi-Agent: questions
- Is GPT-5.5 Pro better than Grok 4.20 Multi-Agent?
- GPT-5.5 Pro (xhigh) leads on quality: 67.0 vs 59.2. The BenchLeader Index combines every independent quality benchmark; GPT-5.5 Pro (xhigh) is ahead overall as of 2026-09-21, but check the category scores for your use.
- Which is cheaper, GPT-5.5 Pro or Grok 4.20 Multi-Agent?
- Grok 4.20 Multi-Agent is cheaper: $1.56 against $67.50 per million tokens, blended at three input tokens per output token.
- Which is faster, GPT-5.5 Pro or Grok 4.20 Multi-Agent?
- Grok 4.20 Multi-Agent streams faster: 304 against 4 output tokens per second.
- Which has the larger context window?
- GPT-5.5 Pro accepts more context: 1.1M against 1M tokens.