GPT-OSS 120B vs LFM2.5-1.2B-Thinking

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

GPT-OSS 120B is clearly ahead on the aggregate, 48 to 33. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-OSS 120B's sharpest advantage is in coding, where it averages 28.1 against 8.2. The single biggest benchmark swing on the page is HumanEval, 43 to 17.

LFM2.5-1.2B-Thinking is the reasoning model in the pair, while GPT-OSS 120B 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-OSS 120B gives you the larger context window at 128K, compared with 32K for LFM2.5-1.2B-Thinking.

Quick Verdict

Pick GPT-OSS 120B if you want the stronger benchmark profile. LFM2.5-1.2B-Thinking only becomes the better choice if you want the stronger reasoning-first profile.

Agentic

GPT-OSS 120B

GPT-OSS 120B

44.8

LFM2.5-1.2B-Thinking

34.1

43
Terminal-Bench 2.0
34
50
BrowseComp
37
43
OSWorld-Verified
32

Coding

GPT-OSS 120B

GPT-OSS 120B

28.1

LFM2.5-1.2B-Thinking

8.2

43
HumanEval
17
29
SWE-bench Verified
10
25
LiveCodeBench
9
31
SWE-bench Pro
7

Multimodal & Grounded

GPT-OSS 120B

GPT-OSS 120B

48.8

LFM2.5-1.2B-Thinking

32.4

42
MMMU-Pro
27
57
OfficeQA Pro
39

Reasoning

GPT-OSS 120B

GPT-OSS 120B

55.2

LFM2.5-1.2B-Thinking

38.4

49
SimpleQA
29
47
MuSR
31
73
BBH
67
58
LongBench v2
39
59
MRCRv2
42

Knowledge

GPT-OSS 120B

GPT-OSS 120B

41.5

LFM2.5-1.2B-Thinking

27

51
MMLU
27
50
GPQA
26
48
SuperGPQA
24
46
OpenBookQA
22
63
MMLU-Pro
51
5
HLE
2
49
FrontierScience
31

Instruction Following

GPT-OSS 120B

GPT-OSS 120B

79

LFM2.5-1.2B-Thinking

72

79
IFEval
72

Multilingual

GPT-OSS 120B

GPT-OSS 120B

70.7

LFM2.5-1.2B-Thinking

60.7

72
MGSM
62
70
MMLU-ProX
60

Mathematics

GPT-OSS 120B

GPT-OSS 120B

59.5

LFM2.5-1.2B-Thinking

42.3

51
AIME 2023
28
53
AIME 2024
30
52
AIME 2025
29
47
HMMT Feb 2023
24
49
HMMT Feb 2024
26
48
HMMT Feb 2025
25
50
BRUMO 2025
27
71
MATH-500
61

Frequently Asked Questions

Which is better, GPT-OSS 120B or LFM2.5-1.2B-Thinking?

GPT-OSS 120B is ahead overall, 48 to 33. The biggest single separator in this matchup is HumanEval, where the scores are 43 and 17.

Which is better for knowledge tasks, GPT-OSS 120B or LFM2.5-1.2B-Thinking?

GPT-OSS 120B has the edge for knowledge tasks in this comparison, averaging 41.5 versus 27. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-OSS 120B or LFM2.5-1.2B-Thinking?

GPT-OSS 120B has the edge for coding in this comparison, averaging 28.1 versus 8.2. Inside this category, HumanEval is the benchmark that creates the most daylight between them.

Which is better for math, GPT-OSS 120B or LFM2.5-1.2B-Thinking?

GPT-OSS 120B has the edge for math in this comparison, averaging 59.5 versus 42.3. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-OSS 120B or LFM2.5-1.2B-Thinking?

GPT-OSS 120B has the edge for reasoning in this comparison, averaging 55.2 versus 38.4. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-OSS 120B or LFM2.5-1.2B-Thinking?

GPT-OSS 120B has the edge for agentic tasks in this comparison, averaging 44.8 versus 34.1. Inside this category, BrowseComp is the benchmark that creates the most daylight between them.

Which is better for multimodal and grounded tasks, GPT-OSS 120B or LFM2.5-1.2B-Thinking?

GPT-OSS 120B has the edge for multimodal and grounded tasks in this comparison, averaging 48.8 versus 32.4. Inside this category, OfficeQA Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-OSS 120B or LFM2.5-1.2B-Thinking?

GPT-OSS 120B has the edge for instruction following in this comparison, averaging 79 versus 72. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, GPT-OSS 120B or LFM2.5-1.2B-Thinking?

GPT-OSS 120B has the edge for multilingual tasks in this comparison, averaging 70.7 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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