Claude Mythos 5.1 vs DeepSeek-V4.1-Flash-1017
Claude Mythos 5.1 and DeepSeek-V4.1-Flash-1017 are closely matched at 44.3 and 51.2 on the LLM Stats Score. DeepSeek-V4.1-Flash-1017 is 38.1x cheaper per token.
Anthropic · DeepSeek · Updated for 2026
Which is better?
Claude Mythos 5.1 and DeepSeek-V4.1-Flash-1017 are closely matched on the overall LLM Stats Score at 44.3 and 51.2.
In the 1 individual benchmarks reported for both models, Claude Mythos 5.1 wins 1; this is a narrower head-to-head signal than the composite indexes.
On price, DeepSeek-V4.1-Flash-1017 is roughly 38.1x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
DeepSeek-V4.1-Flash-1017 also accepts a larger context window (1,048,576 input tokens), making it the stronger choice for long documents and large codebases.
Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.
Choose Claude Mythos 5.1
- you value its reported benchmark strengths — it wins 1 of 1 exact shared results
Choose DeepSeek-V4.1-Flash-1017
- cost matters — it's about 38.1x cheaper per token
- you process long inputs — it offers a 1,048,576 token context window
- you want the most recent training data — it shipped Oct 2026
- you need open weights you can self-host or fine-tune
At a glance
The differences that matter most.
Individual benchmarks
1 reported for Claude Mythos 5.1 · 11 for DeepSeek-V4.1-Flash-1017
Claude Mythos 5.1 outperforms in 1 benchmarks (Terminal-Bench 4.0), while DeepSeek-V4.1-Flash-1017 is better at 0 benchmarks.
Claude Mythos 5.1 significantly outperforms across most benchmarks.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, Claude Mythos 5.1 ($10.00/1M tokens) is 33.3x more expensive than DeepSeek-V4.1-Flash-1017 ($0.30/1M tokens).
For output processing, Claude Mythos 5.1 ($50.00/1M tokens) is 41.7x more expensive than DeepSeek-V4.1-Flash-1017 ($1.20/1M tokens).
In conclusion, Claude Mythos 5.1 is more expensive than DeepSeek-V4.1-Flash-1017.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
DeepSeek-V4.1-Flash-1017 accepts 1,048,576 input tokens compared to Claude Mythos 5.1's 1,000,000 tokens. DeepSeek-V4.1-Flash-1017 can generate longer responses up to 393,216 tokens, while Claude Mythos 5.1 is limited to 128,000 tokens.
Input capabilities
Documented input modalities across available providers
Both Claude Mythos 5.1 and DeepSeek-V4.1-Flash-1017 support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Claude Mythos 5.1
DeepSeek-V4.1-Flash-1017
License
Usage and distribution terms
Claude Mythos 5.1 is licensed under a proprietary license, while DeepSeek-V4.1-Flash-1017 uses MIT.
License differences may affect how you can use these models in commercial or open-source projects.
Proprietary
Closed source
MIT
Open weights
Release Timeline
When each model was launched
Claude Mythos 5.1 was released on 2026-09-01, while DeepSeek-V4.1-Flash-1017 was released on 2026-10-17.
DeepSeek-V4.1-Flash-1017 is 2 months newer than Claude Mythos 5.1.
Sep 1, 2026
1 months ago
Oct 17, 2026
2 days ago
1mo newerKnowledge Cutoff
When training data ends
Neither model specifies a knowledge cutoff date.
Unable to compare the recency of their training data.
Provider Availability
Claude Mythos 5.1 is available from Anthropic. DeepSeek-V4.1-Flash-1017 is available from DeepSeek.
Claude Mythos 5.1
DeepSeek-V4.1-Flash-1017
Outputs Comparison
Judge for yourself.
Run your own prompts against Claude Mythos 5.1 and DeepSeek-V4.1-Flash-1017 side-by-side, then vote on the output you prefer.
FAQ
Common questions about Claude Mythos 5.1 vs DeepSeek-V4.1-Flash-1017.