Claude Mythos Preview vs GLM-5.3-Flash
Claude Mythos Preview significantly outperforms across most benchmarks. GLM-5.3-Flash is 210.5x cheaper per token.
Anthropic · Zhipu AI · Updated for 2026
Which is better?
Claude Mythos Preview outperforms in 2 benchmarks (CharXiv-R, Humanity's Last Exam), while GLM-5.3-Flash is better at 0 benchmarks. Claude Mythos Preview significantly outperforms across most benchmarks.
On price, GLM-5.3-Flash is roughly 210.5x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Based on current benchmark, pricing, and model metadata for 2026.
Choose Claude Mythos Preview
- you want the strongest raw capability — it leads on 2 of 2 shared benchmarks
Choose GLM-5.3-Flash
- cost matters — it's about 210.5x cheaper per token
- you need open weights you can self-host or fine-tune
At a glance
The differences that matter most.
Performance Benchmarks
Comparative analysis across standard metrics
Claude Mythos Preview outperforms in 2 benchmarks (CharXiv-R, Humanity's Last Exam), while GLM-5.3-Flash is better at 0 benchmarks.
Claude Mythos Preview significantly outperforms across most benchmarks.
Arena Performance
Playground indexes and blind preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, Claude Mythos Preview ($25.00/1M tokens) is 166.7x more expensive than GLM-5.3-Flash ($0.15/1M tokens).
For output processing, Claude Mythos Preview ($125.00/1M tokens) is 250.0x more expensive than GLM-5.3-Flash ($0.50/1M tokens).
In conclusion, Claude Mythos Preview is more expensive than GLM-5.3-Flash.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Only GLM-5.3-Flash specifies input context (1,048,576 tokens). Only GLM-5.3-Flash specifies output context (131,072 tokens).
Input Capabilities
Supported data types and modalities
Both Claude Mythos Preview and GLM-5.3-Flash support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Claude Mythos Preview
GLM-5.3-Flash
License
Usage and distribution terms
Claude Mythos Preview is licensed under a proprietary license, while GLM-5.3-Flash 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
GLM-5.3-Flash was released on 2026-08-26, while Claude Mythos Preview's release date is not specified.
We can confirm GLM-5.3-Flash's release timeline, but cannot make a direct age comparison without Claude Mythos Preview's release date.
—
Aug 26, 2026
0 days 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 Preview is available from Anthropic. GLM-5.3-Flash is available from DeepInfra, Novita, ZAI.
Claude Mythos Preview
GLM-5.3-Flash
Outputs Comparison
Judge for yourself.
Run your own prompts against Claude Mythos Preview and GLM-5.3-Flash side-by-side, then vote on the output you prefer.
FAQ
Common questions about Claude Mythos Preview vs GLM-5.3-Flash.