Head-to-head comparison across 1benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
Claude 4 Sonnet
50
Mellum2-12B-A2.5B-Thinking
59
Pick Mellum2-12B-A2.5B-Thinking if you want the stronger benchmark profile. Claude 4 Sonnet only becomes the better choice if coding is the priority or you need the larger 200K context window.
Coding
+2.8 difference
Claude 4 Sonnet
Mellum2-12B-A2.5B-Thinking
$3 / $15
N/A
40 t/s
N/A
1.33s
N/A
200K
128K
Pick Mellum2-12B-A2.5B-Thinking if you want the stronger benchmark profile. Claude 4 Sonnet only becomes the better choice if coding 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 50. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Mellum2-12B-A2.5B-Thinking is the reasoning model in the pair, while Claude 4 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 4 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 50.
Claude 4 Sonnet has the edge for coding in this comparison, averaging 72.7 versus 69.9. Mellum2-12B-A2.5B-Thinking stays close enough that the answer can still flip depending on your workload.
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