Grok 4.1 Fast 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

Grok 4.1 Fast· LFM2.5-350M

Quick Verdict

Pick Grok 4.1 Fast 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.

Grok 4.1 Fast is clearly ahead on the aggregate, 72 to 39. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Grok 4.1 Fast's sharpest advantage is in knowledge, where it averages 70.9 against 23.8. The single biggest benchmark swing on the page is GPQA, 92% to 30.6%.

Grok 4.1 Fast gives you the larger context window at 1M, compared with 32K for LFM2.5-350M.

Operational tradeoffs

ProviderxAILiquidAI
PricePricing unavailableFree*
Speed138 t/sN/A
TTFT0.54sN/A
Context1M32K

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.

BenchmarkGrok 4.1 FastLFM2.5-350M
Agentic
Terminal-Bench 2.074%
BrowseComp73%
OSWorld-Verified66%
Coding
HumanEval86%
SWE-bench Verified68%
LiveCodeBench54%
SWE-bench Pro63%
Multimodal & Grounded
MMMU-Pro91%
OfficeQA Pro83%
Reasoning
MuSR88%
BBH87%
LongBench v287%
MRCRv289%
KnowledgeGrok 4.1 Fast wins
MMLU94%
GPQA92%30.6%
SuperGPQA90%
MMLU-Pro81%20.0%
HLE20%
FrontierScience83%
SimpleQA90%
Instruction FollowingGrok 4.1 Fast wins
IFEval90%77.0%
Multilingual
MGSM88%
MMLU-ProX83%
Mathematics
AIME 202396%
AIME 202498%
AIME 202597%
HMMT Feb 202392%
HMMT Feb 202494%
HMMT Feb 202593%
BRUMO 202595%
MATH-50089%
Frequently Asked Questions (3)

Which is better, Grok 4.1 Fast or LFM2.5-350M?

Grok 4.1 Fast is ahead overall, 72 to 39. The biggest single separator in this matchup is GPQA, where the scores are 92% and 30.6%.

Which is better for knowledge tasks, Grok 4.1 Fast or LFM2.5-350M?

Grok 4.1 Fast has the edge for knowledge tasks in this comparison, averaging 70.9 versus 23.8. Inside this category, GPQA is the benchmark that creates the most daylight between them.

Which is better for instruction following, Grok 4.1 Fast or LFM2.5-350M?

Grok 4.1 Fast has the edge for instruction following in this comparison, averaging 90 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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