Key Takeaways
Claude Sonnet 4.5 wins:
- Larger context window
- Higher intelligence benchmark
- Better at coding
- Supports vision
- Has reasoning mode
- Supports tool calls
GPT-OSS-20b wins:
- Cheaper input tokens
- Cheaper output tokens
- Faster response time
- Better at math
Price Advantage
GPT-OSS-20b
Benchmark Advantage
Claude Sonnet 4.5
Context Window
Claude Sonnet 4.5
Speed
GPT-OSS-20b
Pricing Comparison
Price Comparison
| Metric | Claude Sonnet 4.5 | GPT-OSS-20b | Winner |
|---|---|---|---|
| Input (per 1M tokens) | $3.00 | $0.03 | GPT-OSS-20b |
| Output (per 1M tokens) | $15.00 | $0.14 | GPT-OSS-20b |
| Cache Read (per 1M) | $0.30 | N/A | Claude Sonnet 4.5 |
| Cache Write (per 1M) | $3.75 | N/A | Claude Sonnet 4.5 |
Using a 3:1 input/output ratio, GPT-OSS-20b is 99% cheaper overall.
Claude Sonnet 4.5 Providers
Amazon Bedrock $3.00 (Cheapest)
Google $3.00 (Cheapest)
Anthropic $3.00 (Cheapest)
GPT-OSS-20b Providers
DeepInfra $0.03 (Cheapest)
Parasail $0.04
Novita $0.04
NCompass $0.04
Clarifai $0.04
Benchmark Comparison
6
Benchmarks Compared
4
Claude Sonnet 4.5 Wins
2
GPT-OSS-20b Wins
Benchmark Scores
| Benchmark | Claude Sonnet 4.5 | GPT-OSS-20b | Winner |
|---|---|---|---|
Intelligence Index Overall intelligence score | 37.1 | 24.5 | |
Coding Index Code generation & understanding | 33.5 | 18.5 | |
Math Index Mathematical reasoning | 37.0 | 89.3 | |
MMLU Pro Academic knowledge | 86.0 | 74.8 | |
GPQA Graduate-level science | 72.7 | 68.8 | |
LiveCodeBench Competitive programming | 59.0 | 77.7 |
Claude Sonnet 4.5 significantly outperforms in coding benchmarks.
Cost vs Quality
X-axis:
Y-axis:
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Claude Sonnet 4.5
Other models
Context & Performance
Context Window
Claude Sonnet 4.5
1,000,000
tokens
Max output: 64,000 tokens
GPT-OSS-20b
131,072
tokens
Claude Sonnet 4.5 has a 87% larger context window.
Speed Performance
| Metric | Claude Sonnet 4.5 | GPT-OSS-20b | Winner |
|---|---|---|---|
| Tokens/second | 70.4 tok/s | 293.3 tok/s | |
| Time to First Token | 1.07s | 0.51s |
GPT-OSS-20b responds 316% faster on average.
Capabilities
Feature Comparison
| Feature | Claude Sonnet 4.5 | GPT-OSS-20b |
|---|---|---|
| Vision (Image Input) | ||
| Tool/Function Calls | ||
| Reasoning Mode | ||
| Audio Input | ||
| Audio Output | ||
| PDF Input | ||
| Prompt Caching | ||
| Web Search |
License & Release
| Property | Claude Sonnet 4.5 | GPT-OSS-20b |
|---|---|---|
| License | Proprietary | Open Source |
| Author | Anthropic | OpenAI |
| Released | Sep 2025 | Aug 2025 |
Claude Sonnet 4.5 Modalities
Input
textimagefile
Output
text
GPT-OSS-20b Modalities
Input
text
Output
text