GPT-5.4 vs LFM2.5-1.2B-Instruct

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

GPT-5.4 is clearly ahead on the aggregate, 90 to 30. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5.4's sharpest advantage is in coding, where it averages 84.5 against 7.2. The single biggest benchmark swing on the page is HumanEval, 95 to 14.

GPT-5.4 is also the more expensive model on tokens at $2.50 input / $15.00 output per 1M tokens, versus $0.00 input / $0.00 output per 1M tokens for LFM2.5-1.2B-Instruct. That is roughly Infinityx on output cost alone. GPT-5.4 is the reasoning model in the pair, while LFM2.5-1.2B-Instruct 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 gives you the larger context window at 1.05M, compared with 32K for LFM2.5-1.2B-Instruct.

Quick Verdict

Pick GPT-5.4 if you want the stronger benchmark profile. LFM2.5-1.2B-Instruct 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-5.4

GPT-5.4

87.8

LFM2.5-1.2B-Instruct

25.7

90
Terminal-Bench 2.0
22
88
BrowseComp
31
85
OSWorld-Verified
26

Coding

GPT-5.4

GPT-5.4

84.5

LFM2.5-1.2B-Instruct

7.2

95
HumanEval
14
84
SWE-bench Verified
9
84
LiveCodeBench
8
85
SWE-bench Pro
6

Multimodal & Grounded

GPT-5.4

GPT-5.4

95.5

LFM2.5-1.2B-Instruct

32.4

95
MMMU-Pro
27
96
OfficeQA Pro
39

Reasoning

GPT-5.4

GPT-5.4

95.8

LFM2.5-1.2B-Instruct

32.1

97
SimpleQA
24
94
MuSR
22
97
BBH
59
95
LongBench v2
34
97
MRCRv2
37

Knowledge

GPT-5.4

GPT-5.4

82.6

LFM2.5-1.2B-Instruct

26

99
MMLU
26
98
GPQA
25
96
SuperGPQA
23
94
OpenBookQA
21
93
MMLU-Pro
50
48
HLE
1
91
FrontierScience
30

Instruction Following

GPT-5.4

GPT-5.4

96

LFM2.5-1.2B-Instruct

80

96
IFEval
80

Multilingual

GPT-5.4

GPT-5.4

94.7

LFM2.5-1.2B-Instruct

60.7

96
MGSM
62
94
MMLU-ProX
60

Mathematics

GPT-5.4

GPT-5.4

98.2

LFM2.5-1.2B-Instruct

37

99
AIME 2023
24
99
AIME 2024
26
99
AIME 2025
25
96
HMMT Feb 2023
20
98
HMMT Feb 2024
22
97
HMMT Feb 2025
21
97
BRUMO 2025
23
99
MATH-500
54

Frequently Asked Questions

Which is better, GPT-5.4 or LFM2.5-1.2B-Instruct?

GPT-5.4 is ahead overall, 90 to 30. The biggest single separator in this matchup is HumanEval, where the scores are 95 and 14.

Which is better for knowledge tasks, GPT-5.4 or LFM2.5-1.2B-Instruct?

GPT-5.4 has the edge for knowledge tasks in this comparison, averaging 82.6 versus 26. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5.4 or LFM2.5-1.2B-Instruct?

GPT-5.4 has the edge for coding in this comparison, averaging 84.5 versus 7.2. Inside this category, HumanEval is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5.4 or LFM2.5-1.2B-Instruct?

GPT-5.4 has the edge for math in this comparison, averaging 98.2 versus 37. Inside this category, HMMT Feb 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-5.4 or LFM2.5-1.2B-Instruct?

GPT-5.4 has the edge for reasoning in this comparison, averaging 95.8 versus 32.1. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-5.4 or LFM2.5-1.2B-Instruct?

GPT-5.4 has the edge for agentic tasks in this comparison, averaging 87.8 versus 25.7. 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-5.4 or LFM2.5-1.2B-Instruct?

GPT-5.4 has the edge for multimodal and grounded tasks in this comparison, averaging 95.5 versus 32.4. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-5.4 or LFM2.5-1.2B-Instruct?

GPT-5.4 has the edge for instruction following in this comparison, averaging 96 versus 80. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, GPT-5.4 or LFM2.5-1.2B-Instruct?

GPT-5.4 has the edge for multilingual tasks in this comparison, averaging 94.7 versus 60.7. Inside this category, MGSM is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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