Claude Mythos 5.1 vs o1-preview
Claude Mythos 5.1 leads the LLM Stats Score 45.1 to 16.7. Claude Mythos 5.1 is 1.3x cheaper per token.
Anthropic · OpenAI · Updated for 2026
Which is better?
Claude Mythos 5.1 leads the overall LLM Stats Score 45.1 to 16.7, ranking #31 overall.
On price, Claude Mythos 5.1 is roughly 1.3x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Claude Mythos 5.1 also accepts a larger context window (1,000,000 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
- overall performance matters — it scores 45.1 and ranks #31 on LLM Stats
- your work emphasizes reasoning and coding — it leads those capability indexes
- cost matters — it's about 1.3x cheaper per token
- you process long inputs — it offers a 1,000,000 token context window
- you want the most recent training data — it shipped Sep 2026
Choose o1-preview
- you want predictable pricing at $15.00/M input and $60.00/M output
At a glance
The differences that matter most.
Individual benchmarks
1 reported for Claude Mythos 5.1 · 8 for o1-preview
Claude Mythos 5.1 and o1-previewdon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.
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 1.5x cheaper than o1-preview ($15.00/1M tokens).
For output processing, Claude Mythos 5.1 ($50.00/1M tokens) is 1.2x cheaper than o1-preview ($60.00/1M tokens).
In conclusion, o1-preview is more expensive than Claude Mythos 5.1.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Claude Mythos 5.1 accepts 1,000,000 input tokens compared to o1-preview's 128,000 tokens. Claude Mythos 5.1 can generate longer responses up to 128,000 tokens, while o1-preview is limited to 32,768 tokens.
Input capabilities
Documented input modalities across available providers
Claude Mythos 5.1 supports multimodal inputs, whereas o1-preview does not.
Claude Mythos 5.1 can handle both text and other forms of data like images, making it suitable for multimodal applications.
Claude Mythos 5.1
o1-preview
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
Claude Mythos 5.1 was released on 2026-09-01, while o1-preview was released on 2024-09-12.
Claude Mythos 5.1 is 24 months newer than o1-preview.
Sep 1, 2026
1 weeks ago
2.0yr newerSep 12, 2024
2.0 years ago
Knowledge 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. o1-preview is available from OpenAI, Azure.
Claude Mythos 5.1
o1-preview
Outputs Comparison
Judge for yourself.
Run your own prompts against Claude Mythos 5.1 and o1-preview side-by-side, then vote on the output you prefer.
FAQ
Common questions about Claude Mythos 5.1 vs o1-preview.