Side-by-side benchmark comparison across agentic, coding, multimodal, knowledge, reasoning, and math workflows.
GPT-5.3-Codex-Spark is clearly ahead on the aggregate, 87 to 71. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.3-Codex-Spark's sharpest advantage is in coding, where it averages 82.3 against 55.6. The single biggest benchmark swing on the page is SWE-bench Verified, 80 to 49.3. o3-mini does hit back in instruction following, so the answer changes if that is the part of the workload you care about most.
GPT-5.3-Codex-Spark is also the more expensive model on tokens at $2.00 input / $8.00 output per 1M tokens, versus $1.10 input / $4.40 output per 1M tokens for o3-mini. GPT-5.3-Codex-Spark gives you the larger context window at 256K, compared with 200K for o3-mini.
Pick GPT-5.3-Codex-Spark if you want the stronger benchmark profile. o3-mini only becomes the better choice if instruction following is the priority or you want the cheaper token bill.
GPT-5.3-Codex-Spark
85.6
o3-mini
66.6
GPT-5.3-Codex-Spark
82.3
o3-mini
55.6
GPT-5.3-Codex-Spark
88.3
o3-mini
74.4
GPT-5.3-Codex-Spark
92.7
o3-mini
81.1
GPT-5.3-Codex-Spark
78.3
o3-mini
70.8
GPT-5.3-Codex-Spark
92
o3-mini
93.9
GPT-5.3-Codex-Spark
90.8
o3-mini
73
GPT-5.3-Codex-Spark
96.7
o3-mini
87.3
GPT-5.3-Codex-Spark is ahead overall, 87 to 71. The biggest single separator in this matchup is SWE-bench Verified, where the scores are 80 and 49.3.
GPT-5.3-Codex-Spark has the edge for knowledge tasks in this comparison, averaging 78.3 versus 70.8. Inside this category, FrontierScience is the benchmark that creates the most daylight between them.
GPT-5.3-Codex-Spark has the edge for coding in this comparison, averaging 82.3 versus 55.6. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.
GPT-5.3-Codex-Spark has the edge for math in this comparison, averaging 96.7 versus 87.3. Inside this category, AIME 2024 is the benchmark that creates the most daylight between them.
GPT-5.3-Codex-Spark has the edge for reasoning in this comparison, averaging 92.7 versus 81.1. Inside this category, MRCRv2 is the benchmark that creates the most daylight between them.
GPT-5.3-Codex-Spark has the edge for agentic tasks in this comparison, averaging 85.6 versus 66.6. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.
GPT-5.3-Codex-Spark has the edge for multimodal and grounded tasks in this comparison, averaging 88.3 versus 74.4. Inside this category, OfficeQA Pro is the benchmark that creates the most daylight between them.
o3-mini has the edge for instruction following in this comparison, averaging 93.9 versus 92. Inside this category, IFEval is the benchmark that creates the most daylight between them.
GPT-5.3-Codex-Spark has the edge for multilingual tasks in this comparison, averaging 90.8 versus 73. Inside this category, MMLU-ProX is the benchmark that creates the most daylight between them.
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