GPT-5 (high) vs LFM2.5-1.2B-Thinking

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

GPT-5 (high) is clearly ahead on the aggregate, 79 to 33. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5 (high)'s sharpest advantage is in coding, where it averages 66.1 against 8.2. The single biggest benchmark swing on the page is HumanEval, 85 to 17.

GPT-5 (high) gives you the larger context window at 128K, compared with 32K for LFM2.5-1.2B-Thinking.

Quick Verdict

Pick GPT-5 (high) if you want the stronger benchmark profile. LFM2.5-1.2B-Thinking only becomes the better choice if its workflow or ecosystem matters more than the raw scoreboard.

Agentic

GPT-5 (high)

GPT-5 (high)

75.2

LFM2.5-1.2B-Thinking

34.1

78
Terminal-Bench 2.0
34
75
BrowseComp
37
72
OSWorld-Verified
32

Coding

GPT-5 (high)

GPT-5 (high)

66.1

LFM2.5-1.2B-Thinking

8.2

85
HumanEval
17
67
SWE-bench Verified
10
62
LiveCodeBench
9
70
SWE-bench Pro
7

Multimodal & Grounded

GPT-5 (high)

GPT-5 (high)

89.4

LFM2.5-1.2B-Thinking

32.4

93
MMMU-Pro
27
85
OfficeQA Pro
39

Reasoning

GPT-5 (high)

GPT-5 (high)

85.7

LFM2.5-1.2B-Thinking

38.4

89
SimpleQA
29
87
MuSR
31
94
BBH
67
83
LongBench v2
39
80
MRCRv2
42

Knowledge

GPT-5 (high)

GPT-5 (high)

71.1

LFM2.5-1.2B-Thinking

27

93
MMLU
27
91
GPQA
26
89
SuperGPQA
24
87
OpenBookQA
22
83
MMLU-Pro
51
27
HLE
2
83
FrontierScience
31

Instruction Following

GPT-5 (high)

GPT-5 (high)

91

LFM2.5-1.2B-Thinking

72

91
IFEval
72

Multilingual

GPT-5 (high)

GPT-5 (high)

86.4

LFM2.5-1.2B-Thinking

60.7

89
MGSM
62
85
MMLU-ProX
60

Mathematics

GPT-5 (high)

GPT-5 (high)

94

LFM2.5-1.2B-Thinking

42.3

95
AIME 2023
28
97
AIME 2024
30
96
AIME 2025
29
91
HMMT Feb 2023
24
93
HMMT Feb 2024
26
92
HMMT Feb 2025
25
94
BRUMO 2025
27
94
MATH-500
61

Frequently Asked Questions

Which is better, GPT-5 (high) or LFM2.5-1.2B-Thinking?

GPT-5 (high) is ahead overall, 79 to 33. The biggest single separator in this matchup is HumanEval, where the scores are 85 and 17.

Which is better for knowledge tasks, GPT-5 (high) or LFM2.5-1.2B-Thinking?

GPT-5 (high) has the edge for knowledge tasks in this comparison, averaging 71.1 versus 27. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5 (high) or LFM2.5-1.2B-Thinking?

GPT-5 (high) has the edge for coding in this comparison, averaging 66.1 versus 8.2. Inside this category, HumanEval is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5 (high) or LFM2.5-1.2B-Thinking?

GPT-5 (high) has the edge for math in this comparison, averaging 94 versus 42.3. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-5 (high) or LFM2.5-1.2B-Thinking?

GPT-5 (high) has the edge for reasoning in this comparison, averaging 85.7 versus 38.4. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-5 (high) or LFM2.5-1.2B-Thinking?

GPT-5 (high) has the edge for agentic tasks in this comparison, averaging 75.2 versus 34.1. 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 (high) or LFM2.5-1.2B-Thinking?

GPT-5 (high) has the edge for multimodal and grounded tasks in this comparison, averaging 89.4 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 (high) or LFM2.5-1.2B-Thinking?

GPT-5 (high) has the edge for instruction following in this comparison, averaging 91 versus 72. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, GPT-5 (high) or LFM2.5-1.2B-Thinking?

GPT-5 (high) has the edge for multilingual tasks in this comparison, averaging 86.4 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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