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 53. 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 24.7. The single biggest benchmark swing on the page is LiveCodeBench, 80 to 21.
GPT-5.3-Codex-Spark is also the more expensive model on tokens at $2.00 input / $8.00 output per 1M tokens, versus $0.10 input / $0.40 output per 1M tokens for Gemini 3.1 Flash-Lite. That is roughly 20.0x on output cost alone. GPT-5.3-Codex-Spark is the reasoning model in the pair, while Gemini 3.1 Flash-Lite 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 3.1 Flash-Lite gives you the larger context window at 1M, compared with 256K for GPT-5.3-Codex-Spark.
Pick GPT-5.3-Codex-Spark if you want the stronger benchmark profile. Gemini 3.1 Flash-Lite only becomes the better choice if you want the cheaper token bill or you need the larger 1M context window.
GPT-5.3-Codex-Spark
85.6
Gemini 3.1 Flash-Lite
49.2
GPT-5.3-Codex-Spark
82.3
Gemini 3.1 Flash-Lite
24.7
GPT-5.3-Codex-Spark
88.3
Gemini 3.1 Flash-Lite
73.1
GPT-5.3-Codex-Spark
92.7
Gemini 3.1 Flash-Lite
65.8
GPT-5.3-Codex-Spark
78.3
Gemini 3.1 Flash-Lite
45.3
GPT-5.3-Codex-Spark
92
Gemini 3.1 Flash-Lite
79
GPT-5.3-Codex-Spark
90.8
Gemini 3.1 Flash-Lite
69.8
GPT-5.3-Codex-Spark
96.7
Gemini 3.1 Flash-Lite
66.1
GPT-5.3-Codex-Spark is ahead overall, 87 to 53. The biggest single separator in this matchup is LiveCodeBench, where the scores are 80 and 21.
GPT-5.3-Codex-Spark has the edge for knowledge tasks in this comparison, averaging 78.3 versus 45.3. Inside this category, HLE 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 24.7. Inside this category, LiveCodeBench 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 66.1. Inside this category, AIME 2023 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 65.8. Inside this category, SimpleQA 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 49.2. 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 73.1. Inside this category, OfficeQA Pro is the benchmark that creates the most daylight between them.
GPT-5.3-Codex-Spark has the edge for instruction following in this comparison, averaging 92 versus 79. 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 69.8. Inside this category, MGSM is the benchmark that creates the most daylight between them.
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