GPT-OSS 20B vs Z-1

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

Quick Verdict

Z-1 wins overall with a score of 43 vs 22 (21 point difference).Z-1 wins 4 out of 4 categories.

Knowledge

Z-1

GPT-OSS 20B

28.8

Z-1

49.8

31
MMLU
52
30
GPQA
51
28
SuperGPQA
49
26
OpenBookQA
47

Coding

Z-1

GPT-OSS 20B

23

Z-1

44

23
HumanEval
44

Mathematics

Z-1

GPT-OSS 20B

30

Z-1

51

31
AIME 2023
52
33
AIME 2024
54
32
AIME 2025
53
27
HMMT Feb 2023
48
29
HMMT Feb 2024
50
28
HMMT Feb 2025
49
30
BRUMO 2025
51

Reasoning

Z-1

GPT-OSS 20B

28

Z-1

49

29
SimpleQA
50
27
MuSR
48

Frequently Asked Questions

Which is better, GPT-OSS 20B or Z-1?

Z-1 scores higher overall with 43 vs 22, a difference of 21 points across all benchmarks.

Which is better for knowledge tasks, GPT-OSS 20B or Z-1?

Z-1 leads in knowledge tasks with an average score of 49.8 vs 28.8.

Which is better for coding, GPT-OSS 20B or Z-1?

Z-1 leads in coding with an average score of 44 vs 23.

Which is better for math, GPT-OSS 20B or Z-1?

Z-1 leads in math with an average score of 51 vs 30.

Which is better for reasoning, GPT-OSS 20B or Z-1?

Z-1 leads in reasoning with an average score of 49 vs 28.