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 54. 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 32.8. The single biggest benchmark swing on the page is LiveCodeBench, 80 to 24.
GPT-5.3-Codex-Spark is the reasoning model in the pair, while Grok Code Fast 1 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.
Pick GPT-5.3-Codex-Spark if you want the stronger benchmark profile. Grok Code Fast 1 only becomes the better choice if you would rather avoid the extra latency and token burn of a reasoning model.
GPT-5.3-Codex-Spark
85.6
Grok Code Fast 1
55.7
GPT-5.3-Codex-Spark
82.3
Grok Code Fast 1
32.8
GPT-5.3-Codex-Spark
88.3
Grok Code Fast 1
50.4
GPT-5.3-Codex-Spark
92.7
Grok Code Fast 1
63.7
GPT-5.3-Codex-Spark
78.3
Grok Code Fast 1
48
GPT-5.3-Codex-Spark
92
Grok Code Fast 1
79
GPT-5.3-Codex-Spark
90.8
Grok Code Fast 1
73.7
GPT-5.3-Codex-Spark
96.7
Grok Code Fast 1
67.5
GPT-5.3-Codex-Spark is ahead overall, 87 to 54. The biggest single separator in this matchup is LiveCodeBench, where the scores are 80 and 24.
GPT-5.3-Codex-Spark has the edge for knowledge tasks in this comparison, averaging 78.3 versus 48. 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 32.8. 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 67.5. 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 63.7. 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 55.7. Inside this category, OSWorld-Verified 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 50.4. Inside this category, MMMU-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 73.7. Inside this category, MGSM is the benchmark that creates the most daylight between them.
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