o3 vs Z-1

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

Quick Verdict

o3 wins overall with a score of 67 vs 43 (24 point difference).o3 wins 4 out of 4 categories.

Knowledge

o3

o3

85.3

Z-1

49.8

86
MMLU
52
87
GPQA
51
85
SuperGPQA
49
83
OpenBookQA
47

Coding

o3

o3

78

Z-1

44

78
HumanEval
44

Mathematics

o3

o3

87

Z-1

51

88
AIME 2023
52
90
AIME 2024
54
89
AIME 2025
53
84
HMMT Feb 2023
48
86
HMMT Feb 2024
50
85
HMMT Feb 2025
49
87
BRUMO 2025
51

Reasoning

o3

o3

83

Z-1

49

84
SimpleQA
50
82
MuSR
48

Frequently Asked Questions

Which is better, o3 or Z-1?

o3 scores higher overall with 67 vs 43, a difference of 24 points across all benchmarks.

Which is better for knowledge tasks, o3 or Z-1?

o3 leads in knowledge tasks with an average score of 85.3 vs 49.8.

Which is better for coding, o3 or Z-1?

o3 leads in coding with an average score of 78 vs 44.

Which is better for math, o3 or Z-1?

o3 leads in math with an average score of 87 vs 51.

Which is better for reasoning, o3 or Z-1?

o3 leads in reasoning with an average score of 83 vs 49.