GPT-5.4 Pro vs GPT-OSS 120B

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

GPT-5.4 Pro is clearly ahead on the aggregate, 94 to 50. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5.4 Pro's sharpest advantage is in coding, where it averages 89 against 32.3. The single biggest benchmark swing on the page is LiveCodeBench, 86 to 25.

GPT-5.4 Pro is the reasoning model in the pair, while GPT-OSS 120B 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. GPT-5.4 Pro gives you the larger context window at 1.05M, compared with 128K for GPT-OSS 120B.

Quick Verdict

Pick GPT-5.4 Pro if you want the stronger benchmark profile. GPT-OSS 120B only becomes the better choice if you would rather avoid the extra latency and token burn of a reasoning model.

Knowledge

GPT-5.4 Pro

GPT-5.4 Pro

88.8

GPT-OSS 120B

43.8

99
MMLU
51
99
GPQA
50
97
SuperGPQA
48
94
OpenBookQA
46
94
MMLU-Pro
63
50
HLE
5

Coding

GPT-5.4 Pro

GPT-5.4 Pro

89

GPT-OSS 120B

32.3

95
HumanEval
43
86
SWE-bench Verified
29
86
LiveCodeBench
25

Mathematics

GPT-5.4 Pro

GPT-5.4 Pro

98

GPT-OSS 120B

52.6

99
AIME 2023
51
99
AIME 2024
53
99
AIME 2025
52
96
HMMT Feb 2023
47
98
HMMT Feb 2024
49
97
HMMT Feb 2025
48
97
BRUMO 2025
50
99
MATH-500
71

Reasoning

GPT-5.4 Pro

GPT-5.4 Pro

96.7

GPT-OSS 120B

56.3

97
SimpleQA
49
95
MuSR
47
98
BBH
73

Instruction Following

GPT-5.4 Pro

GPT-5.4 Pro

97

GPT-OSS 120B

79

97
IFEval
79

Multilingual

GPT-5.4 Pro

GPT-5.4 Pro

97

GPT-OSS 120B

72

97
MGSM
72

Frequently Asked Questions

Which is better, GPT-5.4 Pro or GPT-OSS 120B?

GPT-5.4 Pro is ahead overall, 94 to 50. The biggest single separator in this matchup is LiveCodeBench, where the scores are 86 and 25.

Which is better for knowledge tasks, GPT-5.4 Pro or GPT-OSS 120B?

GPT-5.4 Pro has the edge for knowledge tasks in this comparison, averaging 88.8 versus 43.8. Inside this category, GPQA is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5.4 Pro or GPT-OSS 120B?

GPT-5.4 Pro has the edge for coding in this comparison, averaging 89 versus 32.3. Inside this category, LiveCodeBench is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5.4 Pro or GPT-OSS 120B?

GPT-5.4 Pro has the edge for math in this comparison, averaging 98 versus 52.6. Inside this category, HMMT Feb 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-5.4 Pro or GPT-OSS 120B?

GPT-5.4 Pro has the edge for reasoning in this comparison, averaging 96.7 versus 56.3. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-5.4 Pro or GPT-OSS 120B?

GPT-5.4 Pro has the edge for instruction following in this comparison, averaging 97 versus 79. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, GPT-5.4 Pro or GPT-OSS 120B?

GPT-5.4 Pro has the edge for multilingual tasks in this comparison, averaging 97 versus 72. Inside this category, MGSM is the benchmark that creates the most daylight between them.

Last updated: March 9, 2026

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