Side-by-side benchmark comparison across agentic, coding, multimodal, knowledge, reasoning, and math workflows.
o3-pro is clearly ahead on the aggregate, 71 to 65. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
o3-pro's sharpest advantage is in knowledge, where it averages 67.1 against 57.2. The single biggest benchmark swing on the page is HLE, 26 to 9. Mercury 2 does hit back in instruction following, so the answer changes if that is the part of the workload you care about most.
o3-pro gives you the larger context window at 200K, compared with 128K for Mercury 2.
Pick o3-pro if you want the stronger benchmark profile. Mercury 2 only becomes the better choice if instruction following is the priority.
o3-pro
70.4
Mercury 2
63.7
o3-pro
49.2
Mercury 2
41.1
o3-pro
74.1
Mercury 2
68.3
o3-pro
83.6
Mercury 2
80.1
o3-pro
67.1
Mercury 2
57.2
o3-pro
82
Mercury 2
84
o3-pro
81.1
Mercury 2
79.7
o3-pro
89
Mercury 2
80.9
o3-pro is ahead overall, 71 to 65. The biggest single separator in this matchup is HLE, where the scores are 26 and 9.
o3-pro has the edge for knowledge tasks in this comparison, averaging 67.1 versus 57.2. Inside this category, HLE is the benchmark that creates the most daylight between them.
o3-pro has the edge for coding in this comparison, averaging 49.2 versus 41.1. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.
o3-pro has the edge for math in this comparison, averaging 89 versus 80.9. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.
o3-pro has the edge for reasoning in this comparison, averaging 83.6 versus 80.1. Inside this category, MRCRv2 is the benchmark that creates the most daylight between them.
o3-pro has the edge for agentic tasks in this comparison, averaging 70.4 versus 63.7. Inside this category, BrowseComp is the benchmark that creates the most daylight between them.
o3-pro has the edge for multimodal and grounded tasks in this comparison, averaging 74.1 versus 68.3. Inside this category, OfficeQA 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 82. Inside this category, IFEval is the benchmark that creates the most daylight between them.
o3-pro has the edge for multilingual tasks in this comparison, averaging 81.1 versus 79.7. Inside this category, MGSM is the benchmark that creates the most daylight between them.
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