Key Takeaways
GPT-5 Codex wins:
- Larger context window
- Higher intelligence benchmark
- Better at coding
- Better at math
GPT-OSS-20b wins:
- Cheaper input tokens
- Cheaper output tokens
- Faster response time
Price Advantage
GPT-OSS-20b
Benchmark Advantage
GPT-5 Codex
Context Window
GPT-5 Codex
Speed
GPT-OSS-20b
Pricing Comparison
Benchmark Comparison
Context & Performance
Capabilities
Feature Comparison
| Feature | GPT-5 Codex | GPT-OSS-20b |
|---|---|---|
Vision (Image Input) | ||
Tool/Function Calls | ||
Reasoning Mode | ||
Audio Input | ||
Audio Output | ||
PDF Input | ||
Prompt Caching | ||
Web Search |
License & Release
| Property | GPT-5 Codex | GPT-OSS-20b |
|---|---|---|
| License | Proprietary | Open Source |
| Author | OpenAI | OpenAI |
| Released | Sep 2025 | Aug 2025 |
GPT-5 Codex Modalities
Input
textimage
Output
text
GPT-OSS-20b Modalities
Input
text
Output
text