GPT-5.3-Codex-Spark vs DeepSeek V3.1 (Reasoning)

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 41. 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 19.9. The single biggest benchmark swing on the page is SWE-bench Verified, 80 to 14.

GPT-5.3-Codex-Spark gives you the larger context window at 256K, compared with 128K for DeepSeek V3.1 (Reasoning).

Quick Verdict

Pick GPT-5.3-Codex-Spark if you want the stronger benchmark profile. DeepSeek V3.1 (Reasoning) only becomes the better choice if its workflow or ecosystem matters more than the raw scoreboard.

Agentic

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

85.6

DeepSeek V3.1 (Reasoning)

44.2

90
Terminal-Bench 2.0
42
82
BrowseComp
48
83
OSWorld-Verified
44

Coding

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

82.3

DeepSeek V3.1 (Reasoning)

19.9

91
HumanEval
26
80
SWE-bench Verified
14
80
LiveCodeBench
16
85
SWE-bench Pro
25

Multimodal & Grounded

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

88.3

DeepSeek V3.1 (Reasoning)

41.5

86
MMMU-Pro
37
91
OfficeQA Pro
47

Reasoning

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

92.7

DeepSeek V3.1 (Reasoning)

45.8

94
SimpleQA
32
92
MuSR
30
97
BBH
64
91
LongBench v2
57
92
MRCRv2
56

Knowledge

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

78.3

DeepSeek V3.1 (Reasoning)

32.8

97
MMLU
34
95
GPQA
33
93
SuperGPQA
31
91
OpenBookQA
29
88
MMLU-Pro
53
42
HLE
10
88
FrontierScience
37

Instruction Following

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

92

DeepSeek V3.1 (Reasoning)

70

92
IFEval
70

Multilingual

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

90.8

DeepSeek V3.1 (Reasoning)

62.1

94
MGSM
64
89
MMLU-ProX
61

Mathematics

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

96.7

DeepSeek V3.1 (Reasoning)

46.1

98
AIME 2023
34
98
AIME 2024
36
97
AIME 2025
35
94
HMMT Feb 2023
30
96
HMMT Feb 2024
32
95
HMMT Feb 2025
31
95
BRUMO 2025
33
98
MATH-500
62

Frequently Asked Questions

Which is better, GPT-5.3-Codex-Spark or DeepSeek V3.1 (Reasoning)?

GPT-5.3-Codex-Spark is ahead overall, 87 to 41. The biggest single separator in this matchup is SWE-bench Verified, where the scores are 80 and 14.

Which is better for knowledge tasks, GPT-5.3-Codex-Spark or DeepSeek V3.1 (Reasoning)?

GPT-5.3-Codex-Spark has the edge for knowledge tasks in this comparison, averaging 78.3 versus 32.8. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5.3-Codex-Spark or DeepSeek V3.1 (Reasoning)?

GPT-5.3-Codex-Spark has the edge for coding in this comparison, averaging 82.3 versus 19.9. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5.3-Codex-Spark or DeepSeek V3.1 (Reasoning)?

GPT-5.3-Codex-Spark has the edge for math in this comparison, averaging 96.7 versus 46.1. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-5.3-Codex-Spark or DeepSeek V3.1 (Reasoning)?

GPT-5.3-Codex-Spark has the edge for reasoning in this comparison, averaging 92.7 versus 45.8. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-5.3-Codex-Spark or DeepSeek V3.1 (Reasoning)?

GPT-5.3-Codex-Spark has the edge for agentic tasks in this comparison, averaging 85.6 versus 44.2. 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 DeepSeek V3.1 (Reasoning)?

GPT-5.3-Codex-Spark has the edge for multimodal and grounded tasks in this comparison, averaging 88.3 versus 41.5. 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 DeepSeek V3.1 (Reasoning)?

GPT-5.3-Codex-Spark has the edge for instruction following in this comparison, averaging 92 versus 70. 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 DeepSeek V3.1 (Reasoning)?

GPT-5.3-Codex-Spark has the edge for multilingual tasks in this comparison, averaging 90.8 versus 62.1. Inside this category, MGSM is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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