Qwen3.5 397B (Reasoning) vs LFM2.5-1.2B-Instruct

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

Qwen3.5 397B (Reasoning) is clearly ahead on the aggregate, 75 to 30. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Qwen3.5 397B (Reasoning)'s sharpest advantage is in mathematics, where it averages 92.5 against 37. The single biggest benchmark swing on the page is HumanEval, 83 to 14.

Qwen3.5 397B (Reasoning) 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. Qwen3.5 397B (Reasoning) gives you the larger context window at 128K, compared with 32K for LFM2.5-1.2B-Instruct.

Quick Verdict

Pick Qwen3.5 397B (Reasoning) if you want the stronger benchmark profile. LFM2.5-1.2B-Instruct only becomes the better choice if you would rather avoid the extra latency and token burn of a reasoning model.

Agentic

Qwen3.5 397B (Reasoning)

Qwen3.5 397B (Reasoning)

74.8

LFM2.5-1.2B-Instruct

25.7

77
Terminal-Bench 2.0
22
78
BrowseComp
31
70
OSWorld-Verified
26

Coding

Qwen3.5 397B (Reasoning)

Qwen3.5 397B (Reasoning)

62.3

LFM2.5-1.2B-Instruct

7.2

83
HumanEval
14
60
SWE-bench Verified
9
60
LiveCodeBench
8
65
SWE-bench Pro
6

Multimodal & Grounded

Qwen3.5 397B (Reasoning)

Qwen3.5 397B (Reasoning)

70.8

LFM2.5-1.2B-Instruct

32.4

64
MMMU-Pro
27
79
OfficeQA Pro
39

Reasoning

Qwen3.5 397B (Reasoning)

Qwen3.5 397B (Reasoning)

84.2

LFM2.5-1.2B-Instruct

32.1

87
SimpleQA
24
85
MuSR
22
91
BBH
59
80
LongBench v2
34
82
MRCRv2
37

Knowledge

Qwen3.5 397B (Reasoning)

Qwen3.5 397B (Reasoning)

70.1

LFM2.5-1.2B-Instruct

26

91
MMLU
26
89
GPQA
25
87
SuperGPQA
23
85
OpenBookQA
21
81
MMLU-Pro
50
29
HLE
1
81
FrontierScience
30

Instruction Following

Qwen3.5 397B (Reasoning)

Qwen3.5 397B (Reasoning)

89

LFM2.5-1.2B-Instruct

80

89
IFEval
80

Multilingual

Qwen3.5 397B (Reasoning)

Qwen3.5 397B (Reasoning)

87.8

LFM2.5-1.2B-Instruct

60.7

91
MGSM
62
86
MMLU-ProX
60

Mathematics

Qwen3.5 397B (Reasoning)

Qwen3.5 397B (Reasoning)

92.5

LFM2.5-1.2B-Instruct

37

93
AIME 2023
24
95
AIME 2024
26
94
AIME 2025
25
89
HMMT Feb 2023
20
91
HMMT Feb 2024
22
90
HMMT Feb 2025
21
92
BRUMO 2025
23
93
MATH-500
54

Frequently Asked Questions

Which is better, Qwen3.5 397B (Reasoning) or LFM2.5-1.2B-Instruct?

Qwen3.5 397B (Reasoning) is ahead overall, 75 to 30. The biggest single separator in this matchup is HumanEval, where the scores are 83 and 14.

Which is better for knowledge tasks, Qwen3.5 397B (Reasoning) or LFM2.5-1.2B-Instruct?

Qwen3.5 397B (Reasoning) has the edge for knowledge tasks in this comparison, averaging 70.1 versus 26. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, Qwen3.5 397B (Reasoning) or LFM2.5-1.2B-Instruct?

Qwen3.5 397B (Reasoning) has the edge for coding in this comparison, averaging 62.3 versus 7.2. Inside this category, HumanEval is the benchmark that creates the most daylight between them.

Which is better for math, Qwen3.5 397B (Reasoning) or LFM2.5-1.2B-Instruct?

Qwen3.5 397B (Reasoning) has the edge for math in this comparison, averaging 92.5 versus 37. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, Qwen3.5 397B (Reasoning) or LFM2.5-1.2B-Instruct?

Qwen3.5 397B (Reasoning) has the edge for reasoning in this comparison, averaging 84.2 versus 32.1. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, Qwen3.5 397B (Reasoning) or LFM2.5-1.2B-Instruct?

Qwen3.5 397B (Reasoning) has the edge for agentic tasks in this comparison, averaging 74.8 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, Qwen3.5 397B (Reasoning) or LFM2.5-1.2B-Instruct?

Qwen3.5 397B (Reasoning) has the edge for multimodal and grounded tasks in this comparison, averaging 70.8 versus 32.4. Inside this category, OfficeQA Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, Qwen3.5 397B (Reasoning) or LFM2.5-1.2B-Instruct?

Qwen3.5 397B (Reasoning) has the edge for instruction following in this comparison, averaging 89 versus 80. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, Qwen3.5 397B (Reasoning) or LFM2.5-1.2B-Instruct?

Qwen3.5 397B (Reasoning) has the edge for multilingual tasks in this comparison, averaging 87.8 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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