GPT-5.1-Codex-Max vs o4-mini (high)

Side-by-side benchmark comparison across knowledge, coding, math, and reasoning.

Quick Verdict

GPT-5.1-Codex-Max wins overall with a score of 77 vs 65 (12 point difference).GPT-5.1-Codex-Max wins 4 out of 4 categories.

Knowledge

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

95

o4-mini (high)

80.5

98
MMLU
82
96
GPQA
82
94
SuperGPQA
80
92
OpenBookQA
78

Coding

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

94

o4-mini (high)

74

94
HumanEval
74

Mathematics

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

97.1

o4-mini (high)

82

99
AIME 2023
83
99
AIME 2024
85
98
AIME 2025
84
95
HMMT Feb 2023
79
97
HMMT Feb 2024
81
96
HMMT Feb 2025
80
96
BRUMO 2025
82

Reasoning

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

93

o4-mini (high)

79

94
SimpleQA
80
92
MuSR
78

Frequently Asked Questions

Which is better, GPT-5.1-Codex-Max or o4-mini (high)?

GPT-5.1-Codex-Max scores higher overall with 77 vs 65, a difference of 12 points across all benchmarks.

Which is better for knowledge tasks, GPT-5.1-Codex-Max or o4-mini (high)?

GPT-5.1-Codex-Max leads in knowledge tasks with an average score of 95 vs 80.5.

Which is better for coding, GPT-5.1-Codex-Max or o4-mini (high)?

GPT-5.1-Codex-Max leads in coding with an average score of 94 vs 74.

Which is better for math, GPT-5.1-Codex-Max or o4-mini (high)?

GPT-5.1-Codex-Max leads in math with an average score of 97.1 vs 82.

Which is better for reasoning, GPT-5.1-Codex-Max or o4-mini (high)?

GPT-5.1-Codex-Max leads in reasoning with an average score of 93 vs 79.