Mellum2-12B-A2.5B-Instruct vs Nemotron 3 Nano Omni 30B A3B

Pick Nemotron 3 Nano Omni 30B A3B if you want the stronger benchmark profile. Mellum2-12B-A2.5B-Instruct only becomes the better choice if instruction following is the priority or you would rather avoid the extra latency and token burn of a reasoning model.

Nemotron 3 Nano Omni 30B A3B is clearly ahead on the provisional aggregate, 49 to 27. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Nemotron 3 Nano Omni 30B A3B's sharpest advantage is in knowledge, where it averages 75.5 against 40.9. The single biggest benchmark swing on the page is GPQA, 40.9% to 72.2%. Mellum2-12B-A2.5B-Instruct does hit back in instruction following, so the answer changes if that is the part of the workload you care about most.

Nemotron 3 Nano Omni 30B A3B 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. Nemotron 3 Nano Omni 30B A3B gives you the larger context window at 256K, compared with 128K for Mellum2-12B-A2.5B-Instruct.