GPT-5.1 Codex vs Mistral Medium 3.1
Side-by-side benchmark comparison across coding, math, reasoning, speed, and pricing.
GPT-5.1 Codex by OpenAI wins on 10 of 15 benchmarks against Mistral Medium 3.1 by Mistral, which leads on 5. This head-to-head comparison covers coding, math, reasoning, speed, and pricing metrics from our benchmark data.
Category-by-Category Breakdown
General Intelligence: In general intelligence, GPT-5.1 Codex scores 1395 on Chatbot Arena ELO compared to Mistral Medium 3.1's 1250, while GPT-5.1 Codex scores 82.0% on MMLU-Pro compared to Mistral Medium 3.1's 66.0%.
Coding: In coding, GPT-5.1 Codex scores 96.0% on HumanEval+ compared to Mistral Medium 3.1's 77.0%, while GPT-5.1 Codex scores 78.0% on SWE-bench Verified compared to Mistral Medium 3.1's 28.0%, while GPT-5.1 Codex scores 85.0% on LiveCodeBench compared to Mistral Medium 3.1's 34.0%.
Math: In math, GPT-5.1 Codex scores 85.0% on MATH compared to Mistral Medium 3.1's 68.0%, while GPT-5.1 Codex scores 95.0% on GSM8K compared to Mistral Medium 3.1's 86.0%.
Reasoning: In reasoning, GPT-5.1 Codex scores 65.0% on GPQA Diamond compared to Mistral Medium 3.1's 40.0%, while GPT-5.1 Codex scores 52.0% on ARC-AGI compared to Mistral Medium 3.1's 18.0%.
Context: In context, GPT-5.1 Codex scores 400K on Context Length compared to Mistral Medium 3.1's 131K.
Pricing Comparison
GPT-5.1 Codex costs $1.3/1M input tokens and $10.0/1M output tokens, while Mistral Medium 3.1 costs $0.40/1M input and $2.0/1M output. Mistral Medium 3.1 is the more affordable option for API usage.
Speed Comparison
GPT-5.1 Codex generates output at 85 tok/s compared to Mistral Medium 3.1's 110 tok/s, and the time to first token is 400 ms for GPT-5.1 Codex versus 200 ms for Mistral Medium 3.1. Mistral Medium 3.1 delivers faster throughput.
Verdict
For developers prioritizing coding and general intelligence and math, GPT-5.1 Codex has the edge. For those who value affordability and speed, Mistral Medium 3.1 is the stronger choice.
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GPT-5.1 Codex vs Mistral Medium 3.1 — FAQ
Which is better, GPT-5.1 Codex or Mistral Medium 3.1?
GPT-5.1 Codex wins on more benchmarks overall (10 vs 5). However, the best choice depends on your specific needs — each model excels in different areas.
How does GPT-5.1 Codex compare to Mistral Medium 3.1 for coding?
GPT-5.1 Codex is better for coding, scoring 78.0% on SWE-bench Verified compared to 28.0%. SWE-bench tests real-world software engineering by resolving actual GitHub issues.
Is GPT-5.1 Codex cheaper than Mistral Medium 3.1?
Yes, Mistral Medium 3.1 is cheaper. GPT-5.1 Codex costs $1.3/1M input and $10.0/1M output tokens. Mistral Medium 3.1 costs $0.40/1M input and $2.0/1M output tokens.
Which is faster, GPT-5.1 Codex or Mistral Medium 3.1?
Mistral Medium 3.1 is faster, generating output at 110 tok/s compared to 85 tok/s. Faster output speed means shorter wait times for API responses.
What benchmarks does the GPT-5.1 Codex vs Mistral Medium 3.1 comparison cover?
This comparison covers 15 benchmarks including Chatbot Arena ELO, MMLU-Pro, HumanEval+, MATH, GPQA Diamond, SWE-bench Verified, Output Speed, LiveCodeBench, and more. Metrics span general intelligence, coding, math, reasoning, speed, and cost categories.