Head-to-head comparison across 3benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
Grok 4.3
75
Mellum2-12B-A2.5B-Thinking
59
Pick Grok 4.3 if you want the stronger benchmark profile. Mellum2-12B-A2.5B-Thinking only becomes the better choice if coding is the priority.
Coding
+22.6 difference
Knowledge
+3.7 difference
Inst. Following
+4.8 difference
Grok 4.3
Mellum2-12B-A2.5B-Thinking
$1.25 / $2.5
N/A
209 t/s
N/A
12.36s
N/A
1M
128K
Pick Grok 4.3 if you want the stronger benchmark profile. Mellum2-12B-A2.5B-Thinking only becomes the better choice if coding is the priority.
Grok 4.3 is clearly ahead on the provisional aggregate, 75 to 59. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Grok 4.3's sharpest advantage is in instruction following, where it averages 81.3 against 76.5. The single biggest benchmark swing on the page is GPQA, 90.1% to 57.6%. 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.
Grok 4.3 gives you the larger context window at 1M, compared with 128K for Mellum2-12B-A2.5B-Thinking.
Grok 4.3 is ahead on BenchLM's provisional leaderboard, 75 to 59. The biggest single separator in this matchup is GPQA, where the scores are 90.1% and 57.6%.
Mellum2-12B-A2.5B-Thinking has the edge for knowledge tasks in this comparison, averaging 57.6 versus 53.9. 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 47.3. Grok 4.3 stays close enough that the answer can still flip depending on your workload.
Grok 4.3 has the edge for instruction following in this comparison, averaging 81.3 versus 76.5. Mellum2-12B-A2.5B-Thinking stays close enough that the answer can still flip depending on your workload.
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