Head-to-head comparison across 1benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
Mellum2-12B-A2.5B-Instruct
27
Step 3.7 Flash
71
Pick Step 3.7 Flash if you want the stronger benchmark profile. Mellum2-12B-A2.5B-Instruct only becomes the better choice if you would rather avoid the extra latency and token burn of a reasoning model.
Coding
+19.1 difference
Mellum2-12B-A2.5B-Instruct
Step 3.7 Flash
N/A
$0.2 / $1.15
N/A
N/A
N/A
N/A
128K
256K
Pick Step 3.7 Flash if you want the stronger benchmark profile. Mellum2-12B-A2.5B-Instruct only becomes the better choice if you would rather avoid the extra latency and token burn of a reasoning model.
Step 3.7 Flash is clearly ahead on the provisional aggregate, 71 to 27. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Step 3.7 Flash's sharpest advantage is in coding, where it averages 56.3 against 37.2.
Step 3.7 Flash is the reasoning model in the pair, while Mellum2-12B-A2.5B-Instruct 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. Step 3.7 Flash gives you the larger context window at 256K, compared with 128K for Mellum2-12B-A2.5B-Instruct.
Step 3.7 Flash is ahead on BenchLM's provisional leaderboard, 71 to 27.
Step 3.7 Flash has the edge for coding in this comparison, averaging 56.3 versus 37.2. Mellum2-12B-A2.5B-Instruct stays close enough that the answer can still flip depending on your workload.
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