# Gemini 2.5 Deep Think vs Gemini 3.8 Flash

> Gemini 3.8 Flash has enough public results to be ranked (#11); Gemini 2.5 Deep Think does not yet, so treat this comparison as directional.

- Canonical page: https://noometry.com/compare/gemini-2-5-deep-think-vs-gemini-3-8-flash
- Last updated: 2026-10-12
- Shared benchmarks: 0

## Snapshot

| | Gemini 2.5 Deep Think | Gemini 3.8 Flash |
|---|---|---|
| Provider | Google | Google |
| Noometry Index | — | 61.8 |
| Rank | — | 11 |
| Context | — | 1.05M |
| Input $/M | — | $0.75 |
| Output $/M | — | $3.75 |
| Weights | Proprietary | Proprietary |

## Coding

- Gemini 2.5 Deep Think: —
- Gemini 3.8 Flash: 59.2 (#15)

| Benchmark | Gemini 2.5 Deep Think | Gemini 3.8 Flash |
|---|---|---|
| DeepSWE | — | 73.8% |
| FrontierCode | — | 41.2% |
| CursorBench | — | 39.6% |
| LMArena WebDev | — | 1584 |
| FrontierSWE | — | 19.6% |
| SciCode | — | 56.6% |
| WeirdML | — | 84.8% |
| LMArena Coding | — | 1510 |
| ALE-Bench | — | 1,270 |

## Agentic & Tool Use

- Gemini 2.5 Deep Think: —
- Gemini 3.8 Flash: 41.8 (#21)

| Benchmark | Gemini 2.5 Deep Think | Gemini 3.8 Flash |
|---|---|---|
| APEX-Agents | — | 64.3% |
| Remote Labor Index | — | 5.8% |
| GDP.pdf | — | 23.4% |
| Vending-Bench 2 | — | 5,094 |

## Reasoning

- Gemini 2.5 Deep Think: —
- Gemini 3.8 Flash: 76.9 (#5)

| Benchmark | Gemini 2.5 Deep Think | Gemini 3.8 Flash |
|---|---|---|
| ARC-AGI-2 | — | 89.2% |
| NYT Connections (extended) | — | 97.4% |
| ARC-AGI-1 | — | 98.5% |
| CritPt | — | 18.3% |
| Chess Puzzles | — | 61% |
| LMArena Hard Prompts | — | 1508 |
| Mystery Game Puzzles | — | 47% |
| DTBench | — | 95.7% |
| LMCA | — | 52.9% |
| Surface Evolver Bench | — | 76.9% |
| Epoch Capabilities Index | — | 156.71 |

## Math

- Gemini 2.5 Deep Think: —
- Gemini 3.8 Flash: 65.3 (#28)

| Benchmark | Gemini 2.5 Deep Think | Gemini 3.8 Flash |
|---|---|---|
| FrontierMath (Tiers 1-3) | — | 68.4% |
| FrontierMath Tier 4 | — | 22% |
| OTIS Mock AIME 2024-2025 | — | 98.9% |
| ProofBench | — | 48% |
| LMArena Math | — | 1528 |
| FrontierMath (Feb 2025 set) | 29% | — |
| FrontierMath Tier 4 (v1) | 10.4% | — |

## Knowledge

- Gemini 2.5 Deep Think: —
- Gemini 3.8 Flash: 74.8 (#2)

| Benchmark | Gemini 2.5 Deep Think | Gemini 3.8 Flash |
|---|---|---|
| GPQA Diamond | — | 95.4% |
| Humanity's Last Exam | — | 44.5% |
| SimpleQA Verified | — | 69.7% |
| LMArena Expert | — | 1524 |

## Multimodal

- Gemini 2.5 Deep Think: —
- Gemini 3.8 Flash: 40.7 (#45)

| Benchmark | Gemini 2.5 Deep Think | Gemini 3.8 Flash |
|---|---|---|
| LMArena Vision | — | 1314 |
| Blueprint-Bench 2 | — | 38.6% |
| Furniture Assembly | — | 31.7% |

## Multilingual

- Gemini 2.5 Deep Think: —
- Gemini 3.8 Flash: 58.0 (#5)

| Benchmark | Gemini 2.5 Deep Think | Gemini 3.8 Flash |
|---|---|---|
| LMArena Non-English | — | 1491 |
| LMArena Chinese | — | 1554 |
| LMArena French | — | 1498 |
| LMArena German | — | 1493 |
| LMArena Japanese | — | 1502 |
| LMArena Korean | — | 1459 |
| LMArena Russian | — | 1515 |
| LMArena Spanish | — | 1485 |

## Instruction Following

- Gemini 2.5 Deep Think: —
- Gemini 3.8 Flash: 78.0 (#13)

| Benchmark | Gemini 2.5 Deep Think | Gemini 3.8 Flash |
|---|---|---|
| LMArena Instruction Following | — | 1490 |

## Long Context

- Gemini 2.5 Deep Think: —
- Gemini 3.8 Flash: 46.3 (#24)

| Benchmark | Gemini 2.5 Deep Think | Gemini 3.8 Flash |
|---|---|---|
| LMArena Longer Query | — | 1508 |

## Writing & Preference

- Gemini 2.5 Deep Think: —
- Gemini 3.8 Flash: 72.2 (#15)

| Benchmark | Gemini 2.5 Deep Think | Gemini 3.8 Flash |
|---|---|---|
| LMArena Text | — | 1499 |
| LMArena Creative Writing | — | 1492 |
| EQ-Bench Creative Writing | — | 1748 |
| LMArena Multi-Turn | — | 1501 |

## FAQ

### Is Gemini 2.5 Deep Think better than Gemini 3.8 Flash?

Gemini 3.8 Flash has enough public results to be ranked (#11); Gemini 2.5 Deep Think does not yet, so treat this comparison as directional.

### How many benchmarks do Gemini 2.5 Deep Think and Gemini 3.8 Flash share?

0 benchmarks have published results for both models. Gemini 2.5 Deep Think has 2 scored results on Noometry and Gemini 3.8 Flash has 50.