Head-to-head comparison across 3benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
Mellum2-12B-A2.5B-Thinking
59
Qwen3.5-27B
62
Verified leaderboard positions: Mellum2-12B-A2.5B-Thinking unranked · Qwen3.5-27B #21
Pick Qwen3.5-27B if you want the stronger benchmark profile. Mellum2-12B-A2.5B-Thinking only becomes the better choice if coding is the priority.
Coding
+6.9 difference
Knowledge
+23.0 difference
Inst. Following
+18.5 difference
Mellum2-12B-A2.5B-Thinking
Qwen3.5-27B
N/A
$0 / $0
N/A
N/A
N/A
N/A
128K
262K
Pick Qwen3.5-27B if you want the stronger benchmark profile. Mellum2-12B-A2.5B-Thinking only becomes the better choice if coding is the priority.
Qwen3.5-27B has the cleaner provisional overall profile here, landing at 62 versus 59. It is a real lead, but still close enough that category-level strengths matter more than the headline number.
Qwen3.5-27B's sharpest advantage is in knowledge, where it averages 80.6 against 57.6. The single biggest benchmark swing on the page is GPQA, 57.6% to 85.5%. Mellum2-12B-A2.5B-Thinking does hit back in coding, so the answer changes if that is the part of the workload you care about most.
Qwen3.5-27B gives you the larger context window at 262K, compared with 128K for Mellum2-12B-A2.5B-Thinking.
Qwen3.5-27B is ahead on BenchLM's provisional leaderboard, 62 to 59. The biggest single separator in this matchup is GPQA, where the scores are 57.6% and 85.5%.
Qwen3.5-27B has the edge for knowledge tasks in this comparison, averaging 80.6 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 63. Qwen3.5-27B stays close enough that the answer can still flip depending on your workload.
Qwen3.5-27B has the edge for instruction following in this comparison, averaging 95 versus 76.5. Inside this category, IFEval is the benchmark that creates the most daylight between them.
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