o1-preview VS o1-mini

2025-12-20

The artificial intelligence landscape has shifted significantly with OpenAI's release of the o1 series. These models, specifically o1-preview and o1-mini, utilize reinforcement learning to perform "chain-of-thought" reasoning before responding. While both are built for complex problem-solving, they serve vastly different roles in terms of performance, speed, and cost-efficiency.

This comprehensive guide analyzes the technical specifications, benchmark performance, and real-world testing results to help you decide which model fits your specific workflow. Content inspired by the analysis in Benchmarks and specs.

Technical Specifications Comparison

Specification o1-preview o1-mini
Context Window 128K Tokens 128K Tokens
Max Output Tokens 32,768 65,536
Processing Speed ~23 Tokens/sec ~74 Tokens/sec
Knowledge Cutoff October 2023 October 2023

Key Insight: Interestingly, the o1-mini offers a larger output capacity and significantly higher speed, making it the "workhorse" for generation-heavy tasks.

Standardized Benchmarks

Benchmarks reveal that while o1-preview is a generalist with superior graduate-level reasoning, o1-mini punches significantly above its weight in STEM and Coding.

  • 📊 MMLU (Knowledge): o1-preview (90.8%) vs o1-mini (85.2%)
  • 🎓 GPQA (Reasoning): o1-preview (73.3%) vs o1-mini (60.0%)
  • 💻 HumanEval (Coding): Both models tied at 92.4%
  • 🔢 MATH Benchmark: o1-mini (90.0%) slightly beats o1-preview (85.5%)

Real-World Practical Testing

Test 1: Advanced Mathematics

Query: Find the greatest real number less than BD² for a rhombus on a hyperbola.

o1-preview: Failed ❌
Detailed but reached incorrect limit.
o1-mini: Passed ✅
Solved in 23s (Answer: 480).

Test 2: Nuance & Trick Questions

Query: Analysis of marbles in a cup turned upside down.

Winner: o1-preview
The preview model excels at understanding "tricks" and physical nuances that smaller models miss. It correctly identified that gravity would remove marbles from an inverted cup.

Cost-Benefit Analysis

For developers and enterprises, the cost difference is the most deciding factor after reasoning capabilities.

💰 o1-preview: $15.00 per 1M input tokens / $60.00 per 1M output tokens.

💰 o1-mini: $3.00 per 1M input tokens / $12.00 per 1M output tokens.

The o1-mini is roughly 80% cheaper than the preview model.

Final Verdict: Which should you choose?

Select o1-mini if: You are building applications for competitive coding, solving complex math, or require high-speed reasoning at a lower price point.

Select o1-preview if: You need broad general knowledge, deep philosophical reasoning, or high-level creative writing that requires a sophisticated understanding of context.

Frequently Asked Questions (FAQ)

Q1: Does o1-mini replace GPT-4o?

No. While o1-mini is better at reasoning, GPT-4o is still superior for tasks requiring real-time browsing, file uploads, and lower latency for simple chats.

Q2: Why did o1-mini beat o1-preview in math tests?

o1-mini is specifically optimized for STEM fields. Its "reasoning chain" is tuned for logic and calculation rather than broad linguistic nuance.

Q3: Can these models handle large datasets?

Both models feature a 128K context window, allowing them to process substantial documents, though o1-mini can generate twice as much text in a single response.

Q4: Is the reasoning process visible?

In the API and ChatGPT interface, you can see a summary of the reasoning "thought process," though the full raw tokens are not always exposed.