o1 vs Z-1

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

o1 and Z-1 finish on the same overall score, so this is less about a single winner and more about where the edge shows up. The headline says tie; the benchmark table is where the real choice happens.

o1 is the reasoning model in the pair, while Z-1 is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. o1 gives you the larger context window at 200K, compared with 128K for Z-1.

Quick Verdict

Treat this as a split decision. o1 makes more sense if knowledge is the priority or you need the larger 200K context window; Z-1 is the better fit if you would rather avoid the extra latency and token burn of a reasoning model.

Knowledge

o1

o1

83.8

Z-1

44.8

91.8
MMLU
52
75.7
GPQA
51
-
SuperGPQA
49
-
OpenBookQA
47
-
MMLU-Pro
64
-
HLE
6

Coding

o1

o1

41

Z-1

33

41
SWE-bench Verified
33
-
HumanEval
44
-
LiveCodeBench
22

Mathematics

o1

o1

74.3

Z-1

53.8

74.3
AIME 2024
54
-
AIME 2023
52
-
AIME 2025
53
-
HMMT Feb 2023
48
-
HMMT Feb 2024
50
-
HMMT Feb 2025
49
-
BRUMO 2025
51
-
MATH-500
73

Reasoning

Z-1
-
SimpleQA
50
-
MuSR
48
-
BBH
74

Instruction Following

o1

o1

92.2

Z-1

80

92.2
IFEval
80

Multilingual

Z-1
-
MGSM
74

Frequently Asked Questions

Which is better, o1 or Z-1?

o1 and Z-1 are tied on overall score, so the right pick depends on which category matters most for your use case.

Which is better for knowledge tasks, o1 or Z-1?

o1 has the edge for knowledge tasks in this comparison, averaging 83.8 versus 44.8. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, o1 or Z-1?

o1 has the edge for coding in this comparison, averaging 41 versus 33. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.

Which is better for math, o1 or Z-1?

o1 has the edge for math in this comparison, averaging 74.3 versus 53.8. Inside this category, AIME 2024 is the benchmark that creates the most daylight between them.

Which is better for instruction following, o1 or Z-1?

o1 has the edge for instruction following in this comparison, averaging 92.2 versus 80. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Last updated: March 9, 2026

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