Head-to-head comparison across 3benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
GPT-4.1
57
Mellum2-12B-A2.5B-Thinking
59
Pick Mellum2-12B-A2.5B-Thinking if you want the stronger benchmark profile. GPT-4.1 only becomes the better choice if instruction following is the priority or you need the larger 1M context window.
Coding
+15.3 difference
Knowledge
+8.7 difference
Inst. Following
+10.9 difference
GPT-4.1
Mellum2-12B-A2.5B-Thinking
$2 / $8
N/A
108 t/s
N/A
1.02s
N/A
1M
128K
Pick Mellum2-12B-A2.5B-Thinking if you want the stronger benchmark profile. GPT-4.1 only becomes the better choice if instruction following is the priority or you need the larger 1M context window.
Mellum2-12B-A2.5B-Thinking has the cleaner provisional overall profile here, landing at 59 versus 57. It is a real lead, but still close enough that category-level strengths matter more than the headline number.
Mellum2-12B-A2.5B-Thinking's sharpest advantage is in coding, where it averages 69.9 against 54.6. The single biggest benchmark swing on the page is IFEval, 87.4% to 76.5%. GPT-4.1 does hit back in instruction following, 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 GPT-4.1 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. GPT-4.1 gives you the larger context window at 1M, compared with 128K for Mellum2-12B-A2.5B-Thinking.
Mellum2-12B-A2.5B-Thinking is ahead on BenchLM's provisional leaderboard, 59 to 57. The biggest single separator in this matchup is IFEval, where the scores are 87.4% and 76.5%.
GPT-4.1 has the edge for knowledge tasks in this comparison, averaging 66.3 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 54.6. GPT-4.1 stays close enough that the answer can still flip depending on your workload.
GPT-4.1 has the edge for instruction following in this comparison, averaging 87.4 versus 76.5. Inside this category, IFEval is the benchmark that creates the most daylight between them.
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