Side-by-side benchmark comparison across agentic, coding, multimodal, knowledge, reasoning, and math workflows.
GPT-5.3 Instant is clearly ahead on the aggregate, 87 to 60. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.3 Instant's sharpest advantage is in coding, where it averages 78.7 against 37.8. The single biggest benchmark swing on the page is SWE-bench Pro, 83 to 37.
GPT-5.3 Instant 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 GPT-5.3 Instant.
Pick GPT-5.3 Instant if you want the stronger benchmark profile. Claude 3.5 Sonnet only becomes the better choice if you need the larger 200K context window or you would rather avoid the extra latency and token burn of a reasoning model.
GPT-5.3 Instant
82.9
Claude 3.5 Sonnet
55
GPT-5.3 Instant
78.7
Claude 3.5 Sonnet
37.8
GPT-5.3 Instant
95
Claude 3.5 Sonnet
74.8
GPT-5.3 Instant
94.2
Claude 3.5 Sonnet
67.7
GPT-5.3 Instant
80.8
Claude 3.5 Sonnet
50.8
GPT-5.3 Instant
96
Claude 3.5 Sonnet
83
GPT-5.3 Instant
93.4
Claude 3.5 Sonnet
80.5
GPT-5.3 Instant
97.2
Claude 3.5 Sonnet
71.2
GPT-5.3 Instant is ahead overall, 87 to 60. The biggest single separator in this matchup is SWE-bench Pro, where the scores are 83 and 37.
GPT-5.3 Instant has the edge for knowledge tasks in this comparison, averaging 80.8 versus 50.8. Inside this category, HLE is the benchmark that creates the most daylight between them.
GPT-5.3 Instant has the edge for coding in this comparison, averaging 78.7 versus 37.8. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.
GPT-5.3 Instant has the edge for math in this comparison, averaging 97.2 versus 71.2. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.
GPT-5.3 Instant has the edge for reasoning in this comparison, averaging 94.2 versus 67.7. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.
GPT-5.3 Instant has the edge for agentic tasks in this comparison, averaging 82.9 versus 55. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.
GPT-5.3 Instant has the edge for multimodal and grounded tasks in this comparison, averaging 95 versus 74.8. Inside this category, OfficeQA Pro is the benchmark that creates the most daylight between them.
GPT-5.3 Instant has the edge for instruction following in this comparison, averaging 96 versus 83. Inside this category, IFEval is the benchmark that creates the most daylight between them.
GPT-5.3 Instant has the edge for multilingual tasks in this comparison, averaging 93.4 versus 80.5. Inside this category, MMLU-ProX is the benchmark that creates the most daylight between them.
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