GPT-5.1-Codex-Max vs LFM2-24B-A2B

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

GPT-5.1-Codex-Max is clearly ahead on the aggregate, 84 to 38. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5.1-Codex-Max's sharpest advantage is in coding, where it averages 75.5 against 18. The single biggest benchmark swing on the page is SWE-bench Pro, 84 to 19.

GPT-5.1-Codex-Max is also the more expensive model on tokens at $2.00 input / $8.00 output per 1M tokens, versus $0.03 input / $0.12 output per 1M tokens for LFM2-24B-A2B. That is roughly 66.7x on output cost alone. GPT-5.1-Codex-Max is the reasoning model in the pair, while LFM2-24B-A2B 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-5.1-Codex-Max gives you the larger context window at 400K, compared with 32K for LFM2-24B-A2B.

Quick Verdict

Pick GPT-5.1-Codex-Max if you want the stronger benchmark profile. LFM2-24B-A2B only becomes the better choice if you want the cheaper token bill or you would rather avoid the extra latency and token burn of a reasoning model.

Agentic

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

86

LFM2-24B-A2B

33.4

90
Terminal-Bench 2.0
30
85
BrowseComp
38
82
OSWorld-Verified
34

Coding

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

75.5

LFM2-24B-A2B

18

94
HumanEval
42
75
SWE-bench Verified
18
67
LiveCodeBench
17
84
SWE-bench Pro
19

Multimodal & Grounded

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

88.2

LFM2-24B-A2B

41.7

85
MMMU-Pro
39
92
OfficeQA Pro
45

Reasoning

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

92.1

LFM2-24B-A2B

46.6

94
SimpleQA
44
92
MuSR
42
92
BBH
63
90
LongBench v2
48
93
MRCRv2
45

Knowledge

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

72.6

LFM2-24B-A2B

35.6

98
MMLU
46
96
GPQA
45
94
SuperGPQA
43
92
OpenBookQA
41
82
MMLU-Pro
51
27
HLE
4
84
FrontierScience
43

Instruction Following

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

91

LFM2-24B-A2B

68

91
IFEval
68

Multilingual

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

87.7

LFM2-24B-A2B

61.4

89
MGSM
64
87
MMLU-ProX
60

Mathematics

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

94.9

LFM2-24B-A2B

50.4

99
AIME 2023
46
99
AIME 2024
48
98
AIME 2025
47
95
HMMT Feb 2023
42
97
HMMT Feb 2024
44
96
HMMT Feb 2025
43
96
BRUMO 2025
45
93
MATH-500
57

Frequently Asked Questions

Which is better, GPT-5.1-Codex-Max or LFM2-24B-A2B?

GPT-5.1-Codex-Max is ahead overall, 84 to 38. The biggest single separator in this matchup is SWE-bench Pro, where the scores are 84 and 19.

Which is better for knowledge tasks, GPT-5.1-Codex-Max or LFM2-24B-A2B?

GPT-5.1-Codex-Max has the edge for knowledge tasks in this comparison, averaging 72.6 versus 35.6. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5.1-Codex-Max or LFM2-24B-A2B?

GPT-5.1-Codex-Max has the edge for coding in this comparison, averaging 75.5 versus 18. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5.1-Codex-Max or LFM2-24B-A2B?

GPT-5.1-Codex-Max has the edge for math in this comparison, averaging 94.9 versus 50.4. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-5.1-Codex-Max or LFM2-24B-A2B?

GPT-5.1-Codex-Max has the edge for reasoning in this comparison, averaging 92.1 versus 46.6. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-5.1-Codex-Max or LFM2-24B-A2B?

GPT-5.1-Codex-Max has the edge for agentic tasks in this comparison, averaging 86 versus 33.4. 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-5.1-Codex-Max or LFM2-24B-A2B?

GPT-5.1-Codex-Max has the edge for multimodal and grounded tasks in this comparison, averaging 88.2 versus 41.7. Inside this category, OfficeQA Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-5.1-Codex-Max or LFM2-24B-A2B?

GPT-5.1-Codex-Max has the edge for instruction following in this comparison, averaging 91 versus 68. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, GPT-5.1-Codex-Max or LFM2-24B-A2B?

GPT-5.1-Codex-Max has the edge for multilingual tasks in this comparison, averaging 87.7 versus 61.4. Inside this category, MMLU-ProX is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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