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 77. 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 54.1. The single biggest benchmark swing on the page is LiveCodeBench, 75 to 49.
GPT-5.3 Instant is the reasoning model in the pair, while Gemini 3 Pro 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. Gemini 3 Pro gives you the larger context window at 2M, compared with 128K for GPT-5.3 Instant.
Pick GPT-5.3 Instant if you want the stronger benchmark profile. Gemini 3 Pro only becomes the better choice if you need the larger 2M context window or you would rather avoid the extra latency and token burn of a reasoning model.
GPT-5.3 Instant
82.9
Gemini 3 Pro
71.1
GPT-5.3 Instant
78.7
Gemini 3 Pro
54.1
GPT-5.3 Instant
95
Gemini 3 Pro
93.1
GPT-5.3 Instant
94.2
Gemini 3 Pro
91.2
GPT-5.3 Instant
80.8
Gemini 3 Pro
71.8
GPT-5.3 Instant
96
Gemini 3 Pro
88
GPT-5.3 Instant
93.4
Gemini 3 Pro
86.4
GPT-5.3 Instant
97.2
Gemini 3 Pro
94.1
GPT-5.3 Instant is ahead overall, 87 to 77. The biggest single separator in this matchup is LiveCodeBench, where the scores are 75 and 49.
GPT-5.3 Instant has the edge for knowledge tasks in this comparison, averaging 80.8 versus 71.8. 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 54.1. Inside this category, LiveCodeBench 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 94.1. Inside this category, MATH-500 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 91.2. Inside this category, BBH 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 71.1. 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 93.1. 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 88. 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 86.4. Inside this category, MGSM is the benchmark that creates the most daylight between them.
Get notified when new models drop, benchmark scores change, or the leaderboard shifts. One email per week.
Free. No spam. Unsubscribe anytime. We only store derived location metadata for consent routing.