# Claude Mythos Preview vs DeepSeek V4.1 Flash

> Side-by-side benchmark comparison for Claude Mythos Preview and DeepSeek V4.1 Flash across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/claude-mythos-preview-vs-deepseek-v4-1-flash
- Last updated: September 10, 2026

- Shared sourced benchmarks: 2
- HTML indexing: indexable
- Ranking lane: BenchAlign v5

## Quick Verdict

Evidence is too thin for a benchmark verdict: Claude Mythos Preview and DeepSeek V4.1 Flash share only 2 sourced benchmark rows.

## Summary

- Only 2 shared sourced benchmark rows are available. That is not enough for a broad capability verdict, so this mirror does not name an overall winner.
- DeepSeek V4.1 Flash has the lower published output-token price.
- DeepSeek V4.1 Flash has the larger published context window at 1M.

## Model Snapshot

| Property | Claude Mythos Preview | DeepSeek V4.1 Flash |
|----------|----------|----------|
| Creator | Anthropic | DeepSeek |
| Type | Proprietary | Open Weight |
| Reasoning | Reasoning | Reasoning |
| Context | null | 1M |
| Independent public score (not head-to-head) | null | null |
| Benchmarks Covered | 2 | 21 |
| Pricing (input/output) | $25.00 / $125.00 | $0.30 / $1.20 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- Claude Mythos Preview public-lane score: Coming soon
- DeepSeek V4.1 Flash public-lane score: Coming soon

| Benchmark | Claude Mythos Preview | DeepSeek V4.1 Flash | Winner |
|-----------|-----------|-----------|--------|
| CyberGym | 83.1% | 88.1% | DeepSeek V4.1 Flash |
| ExploitGym | 17.5% | 15.3% | Claude Mythos Preview |
| Terminal-Bench 2.1 | Coming soon | 90.6% | Coming soon |
| terminalBench3 | Coming soon | 30% | Coming soon |
| Terminal-Bench 4.0 | Coming soon | 31.20% | Coming soon |
| HLE w/ tools | Coming soon | 63.9% | Coming soon |
| AutomationBench | Coming soon | 54.8% | Coming soon |
| Agents' Last Exam | Coming soon | 31.8% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- Claude Mythos Preview public-lane score: Coming soon
- DeepSeek V4.1 Flash public-lane score: Coming soon

| Benchmark | Claude Mythos Preview | DeepSeek V4.1 Flash | Winner |
|-----------|-----------|-----------|--------|
| Codeforces | Coming soon | 3471.0 | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 90.6% | Coming soon |
| terminalBench3 | Coming soon | 30% | Coming soon |
| DeepSWE | Coming soon | 74.2% | Coming soon |
| ProgramBench | Coming soon | 20.3% | Coming soon |
| NL2Repo | Coming soon | 65.4% | Coming soon |

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- Claude Mythos Preview public-lane score: Coming soon
- DeepSeek V4.1 Flash public-lane score: Coming soon

| Benchmark | Claude Mythos Preview | DeepSeek V4.1 Flash | Winner |
|-----------|-----------|-----------|--------|
| Chartography (tools) | Coming soon | 78.9% | Coming soon |
| BabyVision w/ Python | Coming soon | 89.6% | Coming soon |
| ZeroBench w/ Python | Coming soon | 49.0% | Coming soon |

### Knowledge

- Winner: Insufficient shared evidence
- Claude Mythos Preview public-lane score: Coming soon
- DeepSeek V4.1 Flash public-lane score: Coming soon

| Benchmark | Claude Mythos Preview | DeepSeek V4.1 Flash | Winner |
|-----------|-----------|-----------|--------|
| GPQA | Coming soon | 90.9% | Coming soon |
| GPQA-D | Coming soon | 90.9% | Coming soon |
| HLE | Coming soon | 36.8% | Coming soon |

### Mathematics

- Winner: Insufficient shared evidence
- Claude Mythos Preview public-lane score: Coming soon
- DeepSeek V4.1 Flash public-lane score: Coming soon

| Benchmark | Claude Mythos Preview | DeepSeek V4.1 Flash | Winner |
|-----------|-----------|-----------|--------|
| Apex | Coming soon | 65.6% | Coming soon |

## FAQ

### Is there enough evidence to pick between Claude Mythos Preview and DeepSeek V4.1 Flash?

Not yet. The models share only 2 sourced benchmark rows, so this mirror reports the available measurements and metadata without naming a broad winner.

### What can I compare safely on this page?

Published pricing, context windows, model type, and individual shared benchmark rows are directly comparable. Independent overall scores and non-overlapping benchmark coverage are labeled separately and should not be read as a controlled head-to-head result.

## Related Comparisons

- [Claude Mythos Preview vs Claude Mythos 5](/compare/claude-mythos-5-vs-claude-mythos-preview)
- [DeepSeek V4.1 Flash vs Claude Mythos 5](/compare/claude-mythos-5-vs-deepseek-v4-1-flash)
- [Claude Mythos Preview vs Claude Mythos 5.1](/compare/claude-mythos-5-1-vs-claude-mythos-preview)
- [DeepSeek V4.1 Flash vs Claude Mythos 5.1](/compare/claude-mythos-5-1-vs-deepseek-v4-1-flash)

## Explore More

- [Claude Mythos Preview profile](/models/claude-mythos-preview)
- [DeepSeek V4.1 Flash profile](/models/deepseek-v4-1-flash)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)