Model Comparison
DeepSeek-V4-Flash-Max vs GPT-5.1 ThinkingWhich is better in 2026?
DeepSeek-V4-Flash-Max has a slight edge in benchmark performance. DeepSeek-V4-Flash-Max is 27.5x cheaper per token.
Verdict: DeepSeek-V4-Flash-Max vs GPT-5.1 Thinking — which is better?
DeepSeek-V4-Flash-Max (by DeepSeek) and GPT-5.1 Thinking (by OpenAI) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.
DeepSeek-V4-Flash-Max outperforms in 1 benchmarks (SWE-Bench Verified), while GPT-5.1 Thinking is better at 0 benchmarks. DeepSeek-V4-Flash-Max has a slight edge in benchmark performance.
On price, DeepSeek-V4-Flash-Max is roughly 27.5x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
DeepSeek-V4-Flash-Max also accepts a larger context window (1,048,576 input tokens), making it the stronger choice for long documents and large codebases.
Choose DeepSeek-V4-Flash-Max if…
- cost matters — it's about 27.5x 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 Apr 2026
- you need open weights you can self-host or fine-tune
Choose GPT-5.1 Thinking if…
- you want predictable pricing at $1.25/M input and $10.00/M output
Performance Benchmarks
Comparative analysis across standard metrics
DeepSeek-V4-Flash-Max outperforms in 1 benchmarks (SWE-Bench Verified), while GPT-5.1 Thinking is better at 0 benchmarks.
DeepSeek-V4-Flash-Max has a slight edge in benchmark performance.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, DeepSeek-V4-Flash-Max ($0.10/1M tokens) is 12.5x cheaper than GPT-5.1 Thinking ($1.25/1M tokens).
For output processing, DeepSeek-V4-Flash-Max ($0.20/1M tokens) is 50.0x cheaper than GPT-5.1 Thinking ($10.00/1M tokens).
In conclusion, GPT-5.1 Thinking is more expensive than DeepSeek-V4-Flash-Max.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
DeepSeek-V4-Flash-Max accepts 1,048,576 input tokens compared to GPT-5.1 Thinking's 400,000 tokens. GPT-5.1 Thinking can generate longer responses up to 128,000 tokens, while DeepSeek-V4-Flash-Max is limited to 65,536 tokens.
Input Capabilities
Supported data types and modalities
GPT-5.1 Thinking supports multimodal inputs, whereas DeepSeek-V4-Flash-Max does not.
GPT-5.1 Thinking can handle both text and other forms of data like images, making it suitable for multimodal applications.
DeepSeek-V4-Flash-Max
GPT-5.1 Thinking
License
Usage and distribution terms
DeepSeek-V4-Flash-Max is licensed under MIT, while GPT-5.1 Thinking uses a proprietary license.
License differences may affect how you can use these models in commercial or open-source projects.
MIT
Open weights
Proprietary
Closed source
Release Timeline
When each model was launched
DeepSeek-V4-Flash-Max was released on 2026-04-23, while GPT-5.1 Thinking was released on 2025-11-12.
DeepSeek-V4-Flash-Max is 5 months newer than GPT-5.1 Thinking.
Apr 23, 2026
3 months ago
5mo newerNov 12, 2025
8 months 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
DeepSeek-V4-Flash-Max is available from DeepInfra, DeepSeek, Fireworks, Novita. GPT-5.1 Thinking is available from OpenAI.
DeepSeek-V4-Flash-Max
GPT-5.1 Thinking
Outputs Comparison
Key Takeaways
Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against DeepSeek-V4-Flash-Max and GPT-5.1 Thinking side-by-side, then vote on the output you prefer.
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FAQ
Common questions about DeepSeek-V4-Flash-Max vs GPT-5.1 Thinking.