GPT-5.2 Instant vs GPT-5.1-Codex-Max

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

GPT-5.2 Instant finishes one point ahead overall, 85 to 84. That is enough to call, but not enough to treat as a blowout. This matchup comes down to a few meaningful edges rather than one model dominating the board.

GPT-5.2 Instant's sharpest advantage is in knowledge, where it averages 79.8 against 72.6. The single biggest benchmark swing on the page is HLE, 43 to 27. GPT-5.1-Codex-Max does hit back in agentic, so the answer changes if that is the part of the workload you care about most.

GPT-5.1-Codex-Max is also the more expensive model on tokens at $2.00 input / $8.00 output per 1M tokens, versus $1.50 input / $6.00 output per 1M tokens for GPT-5.2 Instant. GPT-5.1-Codex-Max gives you the larger context window at 400K, compared with 128K for GPT-5.2 Instant.

Quick Verdict

Pick GPT-5.2 Instant if you want the stronger benchmark profile. GPT-5.1-Codex-Max only becomes the better choice if agentic is the priority or you need the larger 400K context window.

Agentic

GPT-5.1-Codex-Max

GPT-5.2 Instant

79.6

GPT-5.1-Codex-Max

86

83
Terminal-Bench 2.0
90
82
BrowseComp
85
74
OSWorld-Verified
82

Coding

Tie

GPT-5.2 Instant

75.5

GPT-5.1-Codex-Max

75.5

87
HumanEval
94
75
SWE-bench Verified
75
74
LiveCodeBench
67
77
SWE-bench Pro
84

Multimodal & Grounded

GPT-5.2 Instant

GPT-5.2 Instant

93.1

GPT-5.1-Codex-Max

88.2

94
MMMU-Pro
85
92
OfficeQA Pro
92

Reasoning

GPT-5.1-Codex-Max

GPT-5.2 Instant

90.9

GPT-5.1-Codex-Max

92.1

95
SimpleQA
94
93
MuSR
92
96
BBH
92
89
LongBench v2
90
84
MRCRv2
93

Knowledge

GPT-5.2 Instant

GPT-5.2 Instant

79.8

GPT-5.1-Codex-Max

72.6

98
MMLU
98
97
GPQA
96
95
SuperGPQA
94
93
OpenBookQA
92
88
MMLU-Pro
82
43
HLE
27
91
FrontierScience
84

Instruction Following

GPT-5.2 Instant

GPT-5.2 Instant

95

GPT-5.1-Codex-Max

91

95
IFEval
91

Multilingual

GPT-5.2 Instant

GPT-5.2 Instant

94.4

GPT-5.1-Codex-Max

87.7

95
MGSM
89
94
MMLU-ProX
87

Mathematics

GPT-5.2 Instant

GPT-5.2 Instant

97.2

GPT-5.1-Codex-Max

94.9

99
AIME 2023
99
99
AIME 2024
99
98
AIME 2025
98
95
HMMT Feb 2023
95
97
HMMT Feb 2024
97
96
HMMT Feb 2025
96
96
BRUMO 2025
96
98
MATH-500
93

Frequently Asked Questions

Which is better, GPT-5.2 Instant or GPT-5.1-Codex-Max?

GPT-5.2 Instant is ahead overall, 85 to 84. The biggest single separator in this matchup is HLE, where the scores are 43 and 27.

Which is better for knowledge tasks, GPT-5.2 Instant or GPT-5.1-Codex-Max?

GPT-5.2 Instant has the edge for knowledge tasks in this comparison, averaging 79.8 versus 72.6. Inside this category, HLE is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5.2 Instant or GPT-5.1-Codex-Max?

GPT-5.2 Instant and GPT-5.1-Codex-Max are effectively tied for coding here, both landing at 75.5 on average.

Which is better for math, GPT-5.2 Instant or GPT-5.1-Codex-Max?

GPT-5.2 Instant has the edge for math in this comparison, averaging 97.2 versus 94.9. Inside this category, MATH-500 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-5.2 Instant or GPT-5.1-Codex-Max?

GPT-5.1-Codex-Max has the edge for reasoning in this comparison, averaging 92.1 versus 90.9. Inside this category, MRCRv2 is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-5.2 Instant or GPT-5.1-Codex-Max?

GPT-5.1-Codex-Max has the edge for agentic tasks in this comparison, averaging 86 versus 79.6. Inside this category, OSWorld-Verified is the benchmark that creates the most daylight between them.

Which is better for multimodal and grounded tasks, GPT-5.2 Instant or GPT-5.1-Codex-Max?

GPT-5.2 Instant has the edge for multimodal and grounded tasks in this comparison, averaging 93.1 versus 88.2. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-5.2 Instant or GPT-5.1-Codex-Max?

GPT-5.2 Instant has the edge for instruction following in this comparison, averaging 95 versus 91. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, GPT-5.2 Instant or GPT-5.1-Codex-Max?

GPT-5.2 Instant has the edge for multilingual tasks in this comparison, averaging 94.4 versus 87.7. Inside this category, MMLU-ProX is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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