GPT-5.2 Pro vs Llama 3.1 405B

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

GPT-5.2 Pro is clearly ahead on the aggregate, 90 to 59. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5.2 Pro's sharpest advantage is in coding, where it averages 84.8 against 40.6. The single biggest benchmark swing on the page is SWE-bench Pro, 89 to 43.

GPT-5.2 Pro is the reasoning model in the pair, while Llama 3.1 405B 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-5.2 Pro gives you the larger context window at 400K, compared with 128K for Llama 3.1 405B.

Quick Verdict

Pick GPT-5.2 Pro if you want the stronger benchmark profile. Llama 3.1 405B only becomes the better choice if you would rather avoid the extra latency and token burn of a reasoning model.

Agentic

GPT-5.2 Pro

GPT-5.2 Pro

85.9

Llama 3.1 405B

53.9

88
Terminal-Bench 2.0
53
88
BrowseComp
58
82
OSWorld-Verified
52

Coding

GPT-5.2 Pro

GPT-5.2 Pro

84.8

Llama 3.1 405B

40.6

93
HumanEval
62
83
SWE-bench Verified
46
81
LiveCodeBench
37
89
SWE-bench Pro
43

Multimodal & Grounded

GPT-5.2 Pro

GPT-5.2 Pro

96

Llama 3.1 405B

62.3

96
MMMU-Pro
60
96
OfficeQA Pro
65

Reasoning

GPT-5.2 Pro

GPT-5.2 Pro

95.2

Llama 3.1 405B

68.3

97
SimpleQA
68
95
MuSR
66
98
BBH
82
93
LongBench v2
68
95
MRCRv2
65

Knowledge

GPT-5.2 Pro

GPT-5.2 Pro

81.5

Llama 3.1 405B

53.2

99
MMLU
70
99
GPQA
70
97
SuperGPQA
68
95
OpenBookQA
66
90
MMLU-Pro
71
44
HLE
7
93
FrontierScience
65

Instruction Following

GPT-5.2 Pro

GPT-5.2 Pro

95

Llama 3.1 405B

86

95
IFEval
86

Multilingual

GPT-5.2 Pro

GPT-5.2 Pro

93.4

Llama 3.1 405B

80.1

96
MGSM
84
92
MMLU-ProX
78

Mathematics

GPT-5.2 Pro

GPT-5.2 Pro

98.2

Llama 3.1 405B

74.9

99
AIME 2023
70
99
AIME 2024
72
99
AIME 2025
71
96
HMMT Feb 2023
66
98
HMMT Feb 2024
68
97
HMMT Feb 2025
67
97
BRUMO 2025
69
99
MATH-500
82

Frequently Asked Questions

Which is better, GPT-5.2 Pro or Llama 3.1 405B?

GPT-5.2 Pro is ahead overall, 90 to 59. The biggest single separator in this matchup is SWE-bench Pro, where the scores are 89 and 43.

Which is better for knowledge tasks, GPT-5.2 Pro or Llama 3.1 405B?

GPT-5.2 Pro has the edge for knowledge tasks in this comparison, averaging 81.5 versus 53.2. Inside this category, HLE is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5.2 Pro or Llama 3.1 405B?

GPT-5.2 Pro has the edge for coding in this comparison, averaging 84.8 versus 40.6. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5.2 Pro or Llama 3.1 405B?

GPT-5.2 Pro has the edge for math in this comparison, averaging 98.2 versus 74.9. Inside this category, HMMT Feb 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-5.2 Pro or Llama 3.1 405B?

GPT-5.2 Pro has the edge for reasoning in this comparison, averaging 95.2 versus 68.3. Inside this category, MRCRv2 is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-5.2 Pro or Llama 3.1 405B?

GPT-5.2 Pro has the edge for agentic tasks in this comparison, averaging 85.9 versus 53.9. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.

Which is better for multimodal and grounded tasks, GPT-5.2 Pro or Llama 3.1 405B?

GPT-5.2 Pro has the edge for multimodal and grounded tasks in this comparison, averaging 96 versus 62.3. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-5.2 Pro or Llama 3.1 405B?

GPT-5.2 Pro has the edge for instruction following in this comparison, averaging 95 versus 86. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, GPT-5.2 Pro or Llama 3.1 405B?

GPT-5.2 Pro has the edge for multilingual tasks in this comparison, averaging 93.4 versus 80.1. Inside this category, MMLU-ProX is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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