Side-by-side benchmark comparison across agentic, coding, multimodal, knowledge, reasoning, and math workflows.
Mercury 2 is clearly ahead on the aggregate, 65 to 60. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Mercury 2's sharpest advantage is in reasoning, where it averages 80.1 against 67.7. The single biggest benchmark swing on the page is MuSR, 82 to 61. Claude 3.5 Sonnet does hit back in multimodal & grounded, so the answer changes if that is the part of the workload you care about most.
Mercury 2 is the reasoning model in the pair, while Claude 3.5 Sonnet 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. Claude 3.5 Sonnet gives you the larger context window at 200K, compared with 128K for Mercury 2.
Pick Mercury 2 if you want the stronger benchmark profile. Claude 3.5 Sonnet only becomes the better choice if multimodal & grounded is the priority or you need the larger 200K context window.
Mercury 2
63.7
Claude 3.5 Sonnet
55
Mercury 2
41.1
Claude 3.5 Sonnet
37.8
Mercury 2
68.3
Claude 3.5 Sonnet
74.8
Mercury 2
80.1
Claude 3.5 Sonnet
67.7
Mercury 2
57.2
Claude 3.5 Sonnet
50.8
Mercury 2
84
Claude 3.5 Sonnet
83
Mercury 2
79.7
Claude 3.5 Sonnet
80.5
Mercury 2
80.9
Claude 3.5 Sonnet
71.2
Mercury 2 is ahead overall, 65 to 60. The biggest single separator in this matchup is MuSR, where the scores are 82 and 61.
Mercury 2 has the edge for knowledge tasks in this comparison, averaging 57.2 versus 50.8. Inside this category, MMLU is the benchmark that creates the most daylight between them.
Mercury 2 has the edge for coding in this comparison, averaging 41.1 versus 37.8. Inside this category, HumanEval is the benchmark that creates the most daylight between them.
Mercury 2 has the edge for math in this comparison, averaging 80.9 versus 71.2. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.
Mercury 2 has the edge for reasoning in this comparison, averaging 80.1 versus 67.7. Inside this category, MuSR is the benchmark that creates the most daylight between them.
Mercury 2 has the edge for agentic tasks in this comparison, averaging 63.7 versus 55. Inside this category, OSWorld-Verified is the benchmark that creates the most daylight between them.
Claude 3.5 Sonnet has the edge for multimodal and grounded tasks in this comparison, averaging 74.8 versus 68.3. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.
Mercury 2 has the edge for instruction following in this comparison, averaging 84 versus 83. Inside this category, IFEval is the benchmark that creates the most daylight between them.
Claude 3.5 Sonnet has the edge for multilingual tasks in this comparison, averaging 80.5 versus 79.7. Inside this category, MGSM is the benchmark that creates the most daylight between them.
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