The eternal rivalry continues. Claude 3.5 Sonnet vs GPT-5. Which model truly reasons better?
Testing Methodology
We designed 50 multi-step reasoning problems across:
- Math: Algebra, calculus, word problems
- Logic: Puzzles, deduction, syllogisms
- Code: Algorithm design, debugging, optimization
- Writing: Nuanced arguments, creative prompts

Results
| Category | Claude 3.5 | GPT-5 |
|---|---|---|
| Math | 94% | 96% |
| Logic | 91% | 88% |
| Code | 89% | 87% |
| Writing | 93% | 90% |
Key Observations
Claude's Strengths
- More nuanced on ethical edge cases
- Better at following complex instructions
- Cleaner, more structured outputs
GPT-5's Strengths
- Faster inference times
- Stronger on pure computation
- Better at role-playing scenarios
Verdict
For developers: Claude edges ahead with its careful reasoning and instruction-following.
For general use: GPT-5 remains more versatile and faster.
Both are excellent. Your choice depends on your specific workflow.