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 66. 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 47.1. The single biggest benchmark swing on the page is LiveCodeBench, 86 to 45.
GPT-5.4 Pro is also the more expensive model on tokens at $30.00 input / $180.00 output per 1M tokens, versus $0.10 input / $0.30 output per 1M tokens for Step 3.5 Flash. That is roughly 600.0x on output cost alone. GPT-5.4 Pro is the reasoning model in the pair, while Step 3.5 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. GPT-5.4 Pro gives you the larger context window at 1.05M, compared with 256K for Step 3.5 Flash.
Pick GPT-5.4 Pro if you want the stronger benchmark profile. Step 3.5 Flash only becomes the better choice if you want the cheaper token bill or you would rather avoid the extra latency and token burn of a reasoning model.
GPT-5.4 Pro
87.4
Step 3.5 Flash
60.2
GPT-5.4 Pro
87.4
Step 3.5 Flash
47.1
GPT-5.4 Pro
94.9
Step 3.5 Flash
66.7
GPT-5.4 Pro
96.1
Step 3.5 Flash
78.3
GPT-5.4 Pro
83.8
Step 3.5 Flash
60.8
GPT-5.4 Pro
97
Step 3.5 Flash
87
GPT-5.4 Pro
95.7
Step 3.5 Flash
82.8
GPT-5.4 Pro
98.2
Step 3.5 Flash
84.5
GPT-5.4 Pro is ahead overall, 91 to 66. The biggest single separator in this matchup is LiveCodeBench, where the scores are 86 and 45.
GPT-5.4 Pro has the edge for knowledge tasks in this comparison, averaging 83.8 versus 60.8. 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 47.1. 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 84.5. 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 78.3. 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 60.2. Inside this category, OSWorld-Verified 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 66.7. 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 87. 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 82.8. Inside this category, MMLU-ProX is the benchmark that creates the most daylight between them.
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