Gemini 3.8 Flash vs Grok 4.5
Gemini 3.8 Flash 
Grok 4.5 Verdict
- Gemini 3.8 Flash (medium) and Grok 4.5 are level on quality (63.5 vs 63.4).
- Gemini 3.8 Flash (medium) is stronger in coding, composite, knowledge, long context, multimodal.
- Grok 4.5 is stronger in agents & tools, human preference, reasoning.
- Gemini 3.8 Flash (medium) is 2.0× cheaper ($1.50 vs $3.00 per 1M blended).
- Gemini 3.8 Flash (medium) streams 4.9× faster (273 vs 56 tokens per second).
| Metric | Gemini 3.8 Flash (medium) | Grok 4.5 |
|---|---|---|
| BenchLeader Index | 63.5 | 63.4 |
| Coding score | 63.6 | 59.9 |
| Composite score | 79.4 | 66.0 |
| Knowledge score | 77.6 | 76.0 |
| Long context score | 68.7 | 66.2 |
| Multimodal score | 68.9 | 64.8 |
| Agents & tools score | – | 58.6 |
| Human preference score | – | 66.9 |
| Reasoning score | – | 68.9 |
| Blended price $/M | $1.50 | $3.00 |
| Output speed | 273 tok/s | 56 tok/s |
| Time to first answer | 13.8 s | 12.7 s |
| Context window | 1M | 500k |
| SimpleBench | – | 70.0% |
| SciCode | 54.4% | – |
| WeirdML | – | 46.4% |
| APEX-Agents | – | 34.2% |
| FrontierCode | – | 42.4% |
| Epoch Capabilities Index | – | 153.9 |
| LMArena Text | – | 1471 |
| LMArena Hard Prompts | – | 1495 |
| LMArena Coding | – | 1523 |
| LMArena WebDev | – | 1556 |
| LMArena Vision | – | 1291 |
| LMArena Agent | – | 3.9 |
| LiveBench | – | 75.8% |
| LiveBench Reasoning | – | 87.2% |
| LiveBench Coding | – | 68.6% |
| LiveBench Agentic Coding | – | 56.5% |
| LiveBench Mathematics | – | 90.8% |
| LiveBench Data Analysis | – | 73.0% |
| LiveBench Language | – | 82.8% |
| AA Intelligence Index | 40 | 39.1 |
| AA-LCR | 84.0% | 79.3% |
| MMMU-Pro | 84.2% | 80.4% |
| AA-Omniscience | 28.6 | 25.3 |
| GPQA Diamond (AA) | 93.5% | 93.1% |
| Humanity's Last Exam (AA) | 42.1% | 42.7% |
| SciCode (AA) | 55.1% | 55.0% |
| Kagi LLM Benchmark | – | 83.5% |
Data as of 2026-09-09. Best configuration of each model; every score links to its source on the model pages.