Head-to-head comparison across 2benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
DeepSeek V4 Flash
57
Mellum2-12B-A2.5B-Thinking
59
Verified leaderboard positions: DeepSeek V4 Flash #30 · Mellum2-12B-A2.5B-Thinking unranked
Pick Mellum2-12B-A2.5B-Thinking if you want the stronger benchmark profile. DeepSeek V4 Flash only becomes the better choice if you need the larger 1M context window or you would rather avoid the extra latency and token burn of a reasoning model.
Coding
+12.8 difference
Knowledge
+12.4 difference
DeepSeek V4 Flash
Mellum2-12B-A2.5B-Thinking
$0.14 / $0.28
N/A
N/A
N/A
N/A
N/A
1M
128K
Pick Mellum2-12B-A2.5B-Thinking if you want the stronger benchmark profile. DeepSeek V4 Flash only becomes the better choice if you need the larger 1M context window or you would rather avoid the extra latency and token burn of a reasoning model.
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 57.1. The single biggest benchmark swing on the page is LiveCodeBench, 55.2% to 69.9%.
Mellum2-12B-A2.5B-Thinking is the reasoning model in the pair, while DeepSeek V4 Flash 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. DeepSeek V4 Flash 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 LiveCodeBench, where the scores are 55.2% and 69.9%.
Mellum2-12B-A2.5B-Thinking has the edge for knowledge tasks in this comparison, averaging 57.6 versus 45.2. 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 57.1. Inside this category, LiveCodeBench is the benchmark that creates the most daylight between them.
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