# Claude Mythos Preview vs DeepSeek V4.1 Flash

> DeepSeek V4.1 Flash has enough public results to be ranked (#38); Claude Mythos Preview does not yet, so treat this comparison as directional.

- Canonical page: https://noometry.com/compare/claude-mythos-preview-vs-deepseek-v4-1-flash
- Last updated: 2026-10-12
- Shared benchmarks: 0

## Summary

- The widest gap is in agentic & tool use, where Claude Mythos Preview leads 41.4 to 31.2.
- DeepSeek V4.1 Flash has downloadable open weights; the other is API-only.

## Snapshot

| | Claude Mythos Preview | DeepSeek V4.1 Flash |
|---|---|---|
| Provider | Anthropic | DeepSeek |
| Noometry Index | 41.2 | 52.8 |
| Rank | — | 38 |
| Context | — | 1M |
| Input $/M | — | $0.15 |
| Output $/M | — | $0.60 |
| Weights | Proprietary | Open |

## Coding

- Claude Mythos Preview: —
- DeepSeek V4.1 Flash: 52.9 (#32)

| Benchmark | Claude Mythos Preview | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena WebDev | — | 1619 |
| SciCode | — | 51.9% |
| LMArena Coding | — | 1506 |
| ALE-Bench | — | 1,092 |

## Agentic & Tool Use

- Claude Mythos Preview: 41.4
- DeepSeek V4.1 Flash: 31.2 (#69)

| Benchmark | Claude Mythos Preview | DeepSeek V4.1 Flash |
|---|---|---|
| APEX-Agents | — | 39.5% |
| ExploitBench | 73.8% | — |
| GDP.pdf | — | 19.8% |
| METR Time Horizons | 85.2% | — |

## Reasoning

- Claude Mythos Preview: —
- DeepSeek V4.1 Flash: 50.2 (#36)

| Benchmark | Claude Mythos Preview | DeepSeek V4.1 Flash |
|---|---|---|
| NYT Connections (extended) | — | 89.6% |
| CritPt | — | 14.3% |
| LMArena Hard Prompts | — | 1483 |
| Mystery Game Puzzles | — | 43% |
| DTBench | — | 89.9% |
| LMCA | — | 47% |
| Surface Evolver Bench | — | 46.3% |
| Epoch Capabilities Index | — | 154.9 |

## Math

- Claude Mythos Preview: —
- DeepSeek V4.1 Flash: 66.7 (#25)

| Benchmark | Claude Mythos Preview | DeepSeek V4.1 Flash |
|---|---|---|
| FrontierMath (Tiers 1-3) | — | 67.4% |
| FrontierMath Tier 4 | — | 26.8% |
| OTIS Mock AIME 2024-2025 | — | 98.3% |
| ProofBench | — | 54% |
| LMArena Math | — | 1477 |

## Knowledge

- Claude Mythos Preview: —
- DeepSeek V4.1 Flash: 57.9 (#38)

| Benchmark | Claude Mythos Preview | DeepSeek V4.1 Flash |
|---|---|---|
| GPQA Diamond | — | 89.8% |
| LMArena Expert | — | 1506 |

## Multimodal

- Claude Mythos Preview: —
- DeepSeek V4.1 Flash: 39.1 (#61)

| Benchmark | Claude Mythos Preview | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena Vision | — | 1277 |
| Furniture Assembly | — | 34.2% |

## Multilingual

- Claude Mythos Preview: —
- DeepSeek V4.1 Flash: 55.0 (#35)

| Benchmark | Claude Mythos Preview | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena Non-English | — | 1448 |
| LMArena Chinese | — | 1497 |
| LMArena French | — | 1452 |
| LMArena German | — | 1484 |
| LMArena Japanese | — | 1412 |
| LMArena Korean | — | 1452 |
| LMArena Russian | — | 1471 |
| LMArena Spanish | — | 1459 |

## Instruction Following

- Claude Mythos Preview: —
- DeepSeek V4.1 Flash: 77.3 (#26)

| Benchmark | Claude Mythos Preview | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena Instruction Following | — | 1474 |

## Long Context

- Claude Mythos Preview: —
- DeepSeek V4.1 Flash: 45.2 (#47)

| Benchmark | Claude Mythos Preview | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena Longer Query | — | 1475 |

## Writing & Preference

- Claude Mythos Preview: —
- DeepSeek V4.1 Flash: 65.4 (#48)

| Benchmark | Claude Mythos Preview | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena Text | — | 1462 |
| LMArena Creative Writing | — | 1435 |
| EQ-Bench Creative Writing | — | 1540 |
| LMArena Multi-Turn | — | 1457 |

## FAQ

### Is Claude Mythos Preview better than DeepSeek V4.1 Flash?

DeepSeek V4.1 Flash has enough public results to be ranked (#38); Claude Mythos Preview does not yet, so treat this comparison as directional.

### How many benchmarks do Claude Mythos Preview and DeepSeek V4.1 Flash share?

0 benchmarks have published results for both models. Claude Mythos Preview has 2 scored results on Noometry and DeepSeek V4.1 Flash has 37.