Side-by-side benchmark comparison across agentic, coding, multimodal, knowledge, reasoning, and math workflows.
GPT-5.4 Pro is clearly ahead on the aggregate, 91 to 65. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.4 Pro's sharpest advantage is in coding, where it averages 87.4 against 41.1. The single biggest benchmark swing on the page is LiveCodeBench, 86 to 38.
GPT-5.4 Pro is also the more expensive model on tokens at $30.00 input / $180.00 output per 1M tokens, versus $0.25 input / $0.75 output per 1M tokens for Mercury 2. That is roughly 240.0x on output cost alone. GPT-5.4 Pro gives you the larger context window at 1.05M, compared with 128K for Mercury 2.
Pick GPT-5.4 Pro if you want the stronger benchmark profile. Mercury 2 only becomes the better choice if you want the cheaper token bill.
GPT-5.4 Pro
87.4
Mercury 2
63.7
GPT-5.4 Pro
87.4
Mercury 2
41.1
GPT-5.4 Pro
94.9
Mercury 2
68.3
GPT-5.4 Pro
96.1
Mercury 2
80.1
GPT-5.4 Pro
83.8
Mercury 2
57.2
GPT-5.4 Pro
97
Mercury 2
84
GPT-5.4 Pro
95.7
Mercury 2
79.7
GPT-5.4 Pro
98.2
Mercury 2
80.9
GPT-5.4 Pro is ahead overall, 91 to 65. The biggest single separator in this matchup is LiveCodeBench, where the scores are 86 and 38.
GPT-5.4 Pro has the edge for knowledge tasks in this comparison, averaging 83.8 versus 57.2. Inside this category, HLE is the benchmark that creates the most daylight between them.
GPT-5.4 Pro has the edge for coding in this comparison, averaging 87.4 versus 41.1. Inside this category, LiveCodeBench is the benchmark that creates the most daylight between them.
GPT-5.4 Pro has the edge for math in this comparison, averaging 98.2 versus 80.9. Inside this category, HMMT Feb 2023 is the benchmark that creates the most daylight between them.
GPT-5.4 Pro has the edge for reasoning in this comparison, averaging 96.1 versus 80.1. Inside this category, MRCRv2 is the benchmark that creates the most daylight between them.
GPT-5.4 Pro has the edge for agentic tasks in this comparison, averaging 87.4 versus 63.7. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.
GPT-5.4 Pro has the edge for multimodal and grounded tasks in this comparison, averaging 94.9 versus 68.3. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.
GPT-5.4 Pro has the edge for instruction following in this comparison, averaging 97 versus 84. Inside this category, IFEval is the benchmark that creates the most daylight between them.
GPT-5.4 Pro has the edge for multilingual tasks in this comparison, averaging 95.7 versus 79.7. Inside this category, MGSM is the benchmark that creates the most daylight between them.
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