GPT-5.3 Codex vs LFM2-24B-A2B

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

GPT-5.3 Codex is clearly ahead on the aggregate, 89 to 38. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5.3 Codex's sharpest advantage is in coding, where it averages 87.3 against 18. The single biggest benchmark swing on the page is SWE-bench Pro, 90 to 19.

GPT-5.3 Codex is also the more expensive model on tokens at $2.50 input / $10.00 output per 1M tokens, versus $0.03 input / $0.12 output per 1M tokens for LFM2-24B-A2B. That is roughly 83.3x on output cost alone. GPT-5.3 Codex 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-5.3 Codex gives you the larger context window at 400K, compared with 32K for LFM2-24B-A2B.

Quick Verdict

Pick GPT-5.3 Codex 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-5.3 Codex

GPT-5.3 Codex

88.1

LFM2-24B-A2B

33.4

90
Terminal-Bench 2.0
30
88
BrowseComp
38
86
OSWorld-Verified
34

Coding

GPT-5.3 Codex

GPT-5.3 Codex

87.3

LFM2-24B-A2B

18

95
HumanEval
42
85
SWE-bench Verified
18
85
LiveCodeBench
17
90
SWE-bench Pro
19

Multimodal & Grounded

GPT-5.3 Codex

GPT-5.3 Codex

91.3

LFM2-24B-A2B

41.7

89
MMMU-Pro
39
94
OfficeQA Pro
45

Reasoning

GPT-5.3 Codex

GPT-5.3 Codex

93.7

LFM2-24B-A2B

46.6

95
SimpleQA
44
93
MuSR
42
98
BBH
63
92
LongBench v2
48
93
MRCRv2
45

Knowledge

GPT-5.3 Codex

GPT-5.3 Codex

80.3

LFM2-24B-A2B

35.6

99
MMLU
46
97
GPQA
45
95
SuperGPQA
43
93
OpenBookQA
41
90
MMLU-Pro
51
44
HLE
4
90
FrontierScience
43

Instruction Following

GPT-5.3 Codex

GPT-5.3 Codex

93

LFM2-24B-A2B

68

93
IFEval
68

Multilingual

GPT-5.3 Codex

GPT-5.3 Codex

92.8

LFM2-24B-A2B

61.4

96
MGSM
64
91
MMLU-ProX
60

Mathematics

GPT-5.3 Codex

GPT-5.3 Codex

97.7

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
99
MATH-500
57

Frequently Asked Questions

Which is better, GPT-5.3 Codex or LFM2-24B-A2B?

GPT-5.3 Codex is ahead overall, 89 to 38. The biggest single separator in this matchup is SWE-bench Pro, where the scores are 90 and 19.

Which is better for knowledge tasks, GPT-5.3 Codex or LFM2-24B-A2B?

GPT-5.3 Codex has the edge for knowledge tasks in this comparison, averaging 80.3 versus 35.6. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5.3 Codex or LFM2-24B-A2B?

GPT-5.3 Codex has the edge for coding in this comparison, averaging 87.3 versus 18. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5.3 Codex or LFM2-24B-A2B?

GPT-5.3 Codex has the edge for math in this comparison, averaging 97.7 versus 50.4. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-5.3 Codex or LFM2-24B-A2B?

GPT-5.3 Codex has the edge for reasoning in this comparison, averaging 93.7 versus 46.6. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-5.3 Codex or LFM2-24B-A2B?

GPT-5.3 Codex has the edge for agentic tasks in this comparison, averaging 88.1 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-5.3 Codex or LFM2-24B-A2B?

GPT-5.3 Codex has the edge for multimodal and grounded tasks in this comparison, averaging 91.3 versus 41.7. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-5.3 Codex or LFM2-24B-A2B?

GPT-5.3 Codex has the edge for instruction following in this comparison, averaging 93 versus 68. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, GPT-5.3 Codex or LFM2-24B-A2B?

GPT-5.3 Codex has the edge for multilingual tasks in this comparison, averaging 92.8 versus 61.4. Inside this category, MGSM is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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