Head-to-head comparison across 1benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
Claude Sonnet 4.5
65
LFM2.5-8B-A1B
50
Pick Claude Sonnet 4.5 if you want the stronger benchmark profile. LFM2.5-8B-A1B only becomes the better choice if you want the cheaper token bill or you want the stronger reasoning-first profile.
Math
+27.1 difference
Claude Sonnet 4.5
LFM2.5-8B-A1B
$3 / $15
$0 / $0
N/A
N/A
N/A
N/A
200K
128K
Pick Claude Sonnet 4.5 if you want the stronger benchmark profile. LFM2.5-8B-A1B only becomes the better choice if you want the cheaper token bill or you want the stronger reasoning-first profile.
Claude Sonnet 4.5 is clearly ahead on the provisional aggregate, 65 to 50. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Claude Sonnet 4.5's sharpest advantage is in mathematics, where it averages 87 against 59.9. The single biggest benchmark swing on the page is AIME 2025, 87% to 42.5%.
Claude Sonnet 4.5 is also the more expensive model on tokens at $3.00 input / $15.00 output per 1M tokens, versus $0.00 input / $0.00 output per 1M tokens for LFM2.5-8B-A1B. That is roughly Infinityx on output cost alone. LFM2.5-8B-A1B is the reasoning model in the pair, while Claude Sonnet 4.5 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. Claude Sonnet 4.5 gives you the larger context window at 200K, compared with 128K for LFM2.5-8B-A1B.
Claude Sonnet 4.5 is ahead on BenchLM's provisional leaderboard, 65 to 50. The biggest single separator in this matchup is AIME 2025, where the scores are 87% and 42.5%.
Claude Sonnet 4.5 has the edge for math in this comparison, averaging 87 versus 59.9. Inside this category, AIME 2025 is the benchmark that creates the most daylight between them.
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