GPT-OSS 120B vs LFM2.5-350M

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

Agentic
Coding
Multimodal & Grounded
Reasoning
Knowledge
Instruction Following
Multilingual
Mathematics

GPT-OSS 120B· LFM2.5-350M

Quick Verdict

Pick GPT-OSS 120B if you want the stronger benchmark profile. LFM2.5-350M only becomes the better choice if its workflow or ecosystem matters more than the raw scoreboard.

GPT-OSS 120B is clearly ahead on the aggregate, 51 to 39. 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 knowledge, where it averages 51.6 against 23.8. The single biggest benchmark swing on the page is MMLU-Pro, 90% to 20.0%.

GPT-OSS 120B gives you the larger context window at 128K, compared with 32K for LFM2.5-350M.

Operational tradeoffs

PriceFree*Free*
Speed262 t/sN/A
TTFT0.79sN/A
Context128K32K

Decision framing

BenchLM keeps the benchmark table and the operator tradeoffs on the same page so a better score does not hide a materially slower, pricier, or smaller-context model.

Runtime metrics show N/A when BenchLM does not have a sourced snapshot for that exact model. The scoring rules and freshness policy are documented on the methodology page.

BenchmarkGPT-OSS 120BLFM2.5-350M
Agentic
Terminal-Bench 2.043%
BrowseComp50%
OSWorld-Verified43%
Coding
HumanEval43%
SWE-bench Verified29%
LiveCodeBench25%
SWE-bench Pro31%
SWE-Rebench33.3%
React Native Evals66.4%
Multimodal & Grounded
MMMU-Pro42%
OfficeQA Pro57%
Reasoning
MuSR47%
BBH73%
LongBench v258%
MRCRv259%
KnowledgeGPT-OSS 120B wins
MMLU90%
GPQA80.9%30.6%
SuperGPQA48%
MMLU-Pro90%20.0%
HLE5%
FrontierScience49%
SimpleQA49%
Instruction FollowingGPT-OSS 120B wins
IFEval79%77.0%
Multilingual
MGSM72%
MMLU-ProX70%
Mathematics
AIME 202351%
AIME 202453%
AIME 202552%
HMMT Feb 202347%
HMMT Feb 202449%
HMMT Feb 202548%
BRUMO 202550%
MATH-50071%
Frequently Asked Questions (3)

Which is better, GPT-OSS 120B or LFM2.5-350M?

GPT-OSS 120B is ahead overall, 51 to 39. The biggest single separator in this matchup is MMLU-Pro, where the scores are 90% and 20.0%.

Which is better for knowledge tasks, GPT-OSS 120B or LFM2.5-350M?

GPT-OSS 120B has the edge for knowledge tasks in this comparison, averaging 51.6 versus 23.8. Inside this category, MMLU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-OSS 120B or LFM2.5-350M?

GPT-OSS 120B has the edge for instruction following in this comparison, averaging 79 versus 77. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Last updated: March 31, 2026

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