GPT-5 (high) vs GPT-OSS 120B

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

Quick Verdict

GPT-5 (high) wins overall with a score of 72 vs 42 (30 point difference).GPT-5 (high) wins 4 out of 4 categories.

Knowledge

GPT-5 (high)

GPT-5 (high)

90

GPT-OSS 120B

48.8

93
MMLU
51
91
GPQA
50
89
SuperGPQA
48
87
OpenBookQA
46

Coding

GPT-5 (high)

GPT-5 (high)

85

GPT-OSS 120B

43

85
HumanEval
43

Mathematics

GPT-5 (high)

GPT-5 (high)

94

GPT-OSS 120B

50

95
AIME 2023
51
97
AIME 2024
53
96
AIME 2025
52
91
HMMT Feb 2023
47
93
HMMT Feb 2024
49
92
HMMT Feb 2025
48
94
BRUMO 2025
50

Reasoning

GPT-5 (high)

GPT-5 (high)

88

GPT-OSS 120B

48

89
SimpleQA
49
87
MuSR
47

Frequently Asked Questions

Which is better, GPT-5 (high) or GPT-OSS 120B?

GPT-5 (high) scores higher overall with 72 vs 42, a difference of 30 points across all benchmarks.

Which is better for knowledge tasks, GPT-5 (high) or GPT-OSS 120B?

GPT-5 (high) leads in knowledge tasks with an average score of 90 vs 48.8.

Which is better for coding, GPT-5 (high) or GPT-OSS 120B?

GPT-5 (high) leads in coding with an average score of 85 vs 43.

Which is better for math, GPT-5 (high) or GPT-OSS 120B?

GPT-5 (high) leads in math with an average score of 94 vs 50.

Which is better for reasoning, GPT-5 (high) or GPT-OSS 120B?

GPT-5 (high) leads in reasoning with an average score of 88 vs 48.