Model Comparison
GPT-5.1 Codex vs Qwen3.5-397B-A17BWhich is better in 2026?
Both models are evenly matched across the benchmarks. Qwen3.5-397B-A17B is 2.5x cheaper per token.
Verdict: GPT-5.1 Codex vs Qwen3.5-397B-A17B — which is better?
GPT-5.1 Codex (by OpenAI) and Qwen3.5-397B-A17B (by Alibaba Cloud / Qwen Team) 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.
GPT-5.1 Codex outperforms in 1 benchmarks (Terminal-Bench 2.0), while Qwen3.5-397B-A17B is better at 1 benchmark (SWE-Bench Verified). Both models are evenly matched across the benchmarks.
On price, Qwen3.5-397B-A17B is roughly 2.5x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-5.1 Codex also accepts a larger context window (400,000 input tokens), making it the stronger choice for long documents and large codebases.
Choose GPT-5.1 Codex if…
- you process long inputs — it offers a 400,000 token context window
Choose Qwen3.5-397B-A17B if…
- cost matters — it's about 2.5x cheaper per token
- you want the most recent training data — it shipped Feb 2026
- you need open weights you can self-host or fine-tune
Performance Benchmarks
Comparative analysis across standard metrics
GPT-5.1 Codex outperforms in 1 benchmarks (Terminal-Bench 2.0), while Qwen3.5-397B-A17B is better at 1 benchmark (SWE-Bench Verified).
Both models are evenly matched across the benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-5.1 Codex ($1.25/1M tokens) is 2.1x more expensive than Qwen3.5-397B-A17B ($0.60/1M tokens).
For output processing, GPT-5.1 Codex ($10.00/1M tokens) is 2.8x more expensive than Qwen3.5-397B-A17B ($3.60/1M tokens).
In conclusion, GPT-5.1 Codex is more expensive than Qwen3.5-397B-A17B.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-5.1 Codex accepts 400,000 input tokens compared to Qwen3.5-397B-A17B's 262,144 tokens. GPT-5.1 Codex can generate longer responses up to 128,000 tokens, while Qwen3.5-397B-A17B is limited to 64,000 tokens.
Input Capabilities
Supported data types and modalities
Both GPT-5.1 Codex and Qwen3.5-397B-A17B support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
GPT-5.1 Codex
Qwen3.5-397B-A17B
License
Usage and distribution terms
GPT-5.1 Codex is licensed under a proprietary license, while Qwen3.5-397B-A17B uses Apache 2.0.
License differences may affect how you can use these models in commercial or open-source projects.
Proprietary
Closed source
Apache 2.0
Open weights
Release Timeline
When each model was launched
GPT-5.1 Codex was released on 2025-11-19, while Qwen3.5-397B-A17B was released on 2026-02-16.
Qwen3.5-397B-A17B is 3 months newer than GPT-5.1 Codex.
Nov 19, 2025
8 months ago
Feb 16, 2026
5 months ago
2mo newerKnowledge Cutoff
When training data ends
GPT-5.1 Codex has a documented knowledge cutoff of 2024-09-30, while Qwen3.5-397B-A17B's cutoff date is not specified.
We can confirm GPT-5.1 Codex's training data extends to 2024-09-30, but cannot make a direct comparison without Qwen3.5-397B-A17B's cutoff date.
Sep 2024
—
Provider Availability
GPT-5.1 Codex is available from OpenAI. Qwen3.5-397B-A17B is available from Novita.
GPT-5.1 Codex
Qwen3.5-397B-A17B
Outputs Comparison
Key Takeaways
Qwen3.5-397B-A17B
View detailsAlibaba Cloud / Qwen Team
Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against GPT-5.1 Codex and Qwen3.5-397B-A17B side-by-side, then vote on the output you prefer.
| Feature | | |
|---|
FAQ
Common questions about GPT-5.1 Codex vs Qwen3.5-397B-A17B.