Head-to-head comparison across 2benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
Claude 3.5 Sonnet
40
Mellum2-12B-A2.5B-Thinking
59
Pick Mellum2-12B-A2.5B-Thinking if you want the stronger benchmark profile. Claude 3.5 Sonnet only becomes the better choice if knowledge is the priority or you need the larger 200K context window.
Coding
+20.9 difference
Knowledge
+1.8 difference
Claude 3.5 Sonnet
Mellum2-12B-A2.5B-Thinking
$3 / $15
N/A
N/A
N/A
N/A
N/A
200K
128K
Pick Mellum2-12B-A2.5B-Thinking if you want the stronger benchmark profile. Claude 3.5 Sonnet only becomes the better choice if knowledge is the priority or you need the larger 200K context window.
Mellum2-12B-A2.5B-Thinking is clearly ahead on the provisional aggregate, 59 to 40. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Mellum2-12B-A2.5B-Thinking's sharpest advantage is in coding, where it averages 69.9 against 49. The single biggest benchmark swing on the page is GPQA, 59.4% to 57.6%. Claude 3.5 Sonnet does hit back in knowledge, so the answer changes if that is the part of the workload you care about most.
Mellum2-12B-A2.5B-Thinking is the reasoning model in the pair, while Claude 3.5 Sonnet 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 3.5 Sonnet gives you the larger context window at 200K, compared with 128K for Mellum2-12B-A2.5B-Thinking.
Mellum2-12B-A2.5B-Thinking is ahead on BenchLM's provisional leaderboard, 59 to 40. The biggest single separator in this matchup is GPQA, where the scores are 59.4% and 57.6%.
Claude 3.5 Sonnet has the edge for knowledge tasks in this comparison, averaging 59.4 versus 57.6. Inside this category, GPQA is the benchmark that creates the most daylight between them.
Mellum2-12B-A2.5B-Thinking has the edge for coding in this comparison, averaging 69.9 versus 49. Claude 3.5 Sonnet stays close enough that the answer can still flip depending on your workload.
For engineers, researchers, and the plain curious — a weekly brief on new models, ranking shifts, and pricing changes.
Free. No spam. Unsubscribe anytime.