GPT-5.3-Codex-Spark vs Gemini 3 Pro

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 77. 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 54.1. The single biggest benchmark swing on the page is LiveCodeBench, 80 to 49. Gemini 3 Pro does hit back in multimodal & grounded, so the answer changes if that is the part of the workload you care about most.

GPT-5.3-Codex-Spark 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 256K for GPT-5.3-Codex-Spark.

Quick Verdict

Pick GPT-5.3-Codex-Spark if you want the stronger benchmark profile. Gemini 3 Pro only becomes the better choice if multimodal & grounded is the priority or you need the larger 2M context window.

Agentic

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

85.6

Gemini 3 Pro

71.1

90
Terminal-Bench 2.0
68
82
BrowseComp
83
83
OSWorld-Verified
66

Coding

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

82.3

Gemini 3 Pro

54.1

91
HumanEval
91
80
SWE-bench Verified
59
80
LiveCodeBench
49
85
SWE-bench Pro
58

Multimodal & Grounded

Gemini 3 Pro

GPT-5.3-Codex-Spark

88.3

Gemini 3 Pro

93.1

86
MMMU-Pro
94
91
OfficeQA Pro
92

Reasoning

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

92.7

Gemini 3 Pro

91.2

94
SimpleQA
95
92
MuSR
93
97
BBH
90
91
LongBench v2
90
92
MRCRv2
87

Knowledge

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

78.3

Gemini 3 Pro

71.8

97
MMLU
99
95
GPQA
97
93
SuperGPQA
95
91
OpenBookQA
93
88
MMLU-Pro
83
42
HLE
20
88
FrontierScience
86

Instruction Following

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

92

Gemini 3 Pro

88

92
IFEval
88

Multilingual

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

90.8

Gemini 3 Pro

86.4

94
MGSM
89
89
MMLU-ProX
85

Mathematics

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

96.7

Gemini 3 Pro

94.1

98
AIME 2023
99
98
AIME 2024
99
97
AIME 2025
98
94
HMMT Feb 2023
95
96
HMMT Feb 2024
97
95
HMMT Feb 2025
96
95
BRUMO 2025
96
98
MATH-500
91

Frequently Asked Questions

Which is better, GPT-5.3-Codex-Spark or Gemini 3 Pro?

GPT-5.3-Codex-Spark is ahead overall, 87 to 77. The biggest single separator in this matchup is LiveCodeBench, where the scores are 80 and 49.

Which is better for knowledge tasks, GPT-5.3-Codex-Spark or Gemini 3 Pro?

GPT-5.3-Codex-Spark has the edge for knowledge tasks in this comparison, averaging 78.3 versus 71.8. Inside this category, HLE is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5.3-Codex-Spark or Gemini 3 Pro?

GPT-5.3-Codex-Spark has the edge for coding in this comparison, averaging 82.3 versus 54.1. Inside this category, LiveCodeBench is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5.3-Codex-Spark or Gemini 3 Pro?

GPT-5.3-Codex-Spark has the edge for math in this comparison, averaging 96.7 versus 94.1. Inside this category, MATH-500 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-5.3-Codex-Spark or Gemini 3 Pro?

GPT-5.3-Codex-Spark has the edge for reasoning in this comparison, averaging 92.7 versus 91.2. Inside this category, BBH is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-5.3-Codex-Spark or Gemini 3 Pro?

GPT-5.3-Codex-Spark has the edge for agentic tasks in this comparison, averaging 85.6 versus 71.1. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.

Which is better for multimodal and grounded tasks, GPT-5.3-Codex-Spark or Gemini 3 Pro?

Gemini 3 Pro has the edge for multimodal and grounded tasks in this comparison, averaging 93.1 versus 88.3. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-5.3-Codex-Spark or Gemini 3 Pro?

GPT-5.3-Codex-Spark has the edge for instruction following in this comparison, averaging 92 versus 88. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, GPT-5.3-Codex-Spark or Gemini 3 Pro?

GPT-5.3-Codex-Spark has the edge for multilingual tasks in this comparison, averaging 90.8 versus 86.4. Inside this category, MGSM is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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