| Claude Mythos | DeepSeek V4 | |
|---|---|---|
| arenaElo | 1478 | 1395 |
| humanEval | 98.7 | 91 |
| sweBench | 93.9 | 62 |
| mmlu | 94.2 | 91.5 |
| gpqa | 94.6 | 73 |
| aime | 97.6 | 90 |
| Price in/out ($/M) | $25 / $125 | $1.74 / $3.48 |
DeepSeek V4 is the open-weights flagship of 2026: MIT-licensed, 1M context, ~14× cheaper input than Mythos, and self-hostable. Mythos retains the capability lead by 20+ points on GPQA and SWE-bench, plus its cybersecurity capabilities are unmatched. Pick V4 for any team that needs to deploy frontier-tier reasoning on its own hardware or under data residency requirements. Pick Mythos only if you have access and your use case justifies a 14× per-token cost.