In short
How they differ.
Worked out from the figures below. Prices and specs are the makers' own, read Oct 20, 2026.
- DeepSeek-V4.1-Flash-1017 can be downloaded and run on your own machine; Claude Mythos 5.1 can't.
- No independent board we follow ranks both models yet.
Side by side
The specs.
| Claude Mythos 5.1 | DeepSeek-V4.1-Flash-1017 | |
|---|---|---|
| Made by | Anthropic · US | DeepSeek · China |
| Released | Sep 1, 2026 | Oct 17, 2026 |
| Price per 1M tokens | No public price | $0.30 in / $1.20 out (peak-hours price) |
| Context window | Not stated | 1M |
| Takes in | Not stated | text, image |
| Download and run it yourself | No | Yes (MIT) |
| Size | Not published | 552B backbone parameters parameters, 8B per token during prefill, 16B during decode active |
| Maker says | “Our most capable model for cybersecurity and biology research.” | “Stronger benchmark performance, faster task completion, and shorter outputs than the previous version.” |
| Sources | Prices, Oct 20, 2026 · Description | Prices, Oct 20, 2026 · Description |
Independent tests
Where they place.
Position on each board we follow (1 is best). Epoch AI's and Vectara's scores are shown; the other boards are linked for their own figures.
More comparisons