GPT-5.3 Codex vs Ministral 3 8B (Reasoning)

Side-by-side benchmark comparison across agentic, coding, multimodal, knowledge, reasoning, and math workflows.

GPT-5.3 Codex is clearly ahead on the aggregate, 89 to 36. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5.3 Codex's sharpest advantage is in coding, where it averages 87.3 against 15.2. The single biggest benchmark swing on the page is SWE-bench Pro, 90 to 14.

GPT-5.3 Codex is also the more expensive model on tokens at $2.50 input / $10.00 output per 1M tokens, versus $0.00 input / $0.00 output per 1M tokens for Ministral 3 8B (Reasoning). That is roughly Infinityx on output cost alone. GPT-5.3 Codex gives you the larger context window at 400K, compared with 128K for Ministral 3 8B (Reasoning).

Quick Verdict

Pick GPT-5.3 Codex if you want the stronger benchmark profile. Ministral 3 8B (Reasoning) only becomes the better choice if you want the cheaper token bill.

Agentic

GPT-5.3 Codex

GPT-5.3 Codex

88.1

Ministral 3 8B (Reasoning)

38.5

90
Terminal-Bench 2.0
39
88
BrowseComp
41
86
OSWorld-Verified
36

Coding

GPT-5.3 Codex

GPT-5.3 Codex

87.3

Ministral 3 8B (Reasoning)

15.2

95
HumanEval
24
85
SWE-bench Verified
17
85
LiveCodeBench
16
90
SWE-bench Pro
14

Multimodal & Grounded

GPT-5.3 Codex

GPT-5.3 Codex

91.3

Ministral 3 8B (Reasoning)

33.4

89
MMMU-Pro
28
94
OfficeQA Pro
40

Reasoning

GPT-5.3 Codex

GPT-5.3 Codex

93.7

Ministral 3 8B (Reasoning)

42.1

95
SimpleQA
32
93
MuSR
33
98
BBH
70
92
LongBench v2
44
93
MRCRv2
47

Knowledge

GPT-5.3 Codex

GPT-5.3 Codex

80.3

Ministral 3 8B (Reasoning)

30

99
MMLU
30
97
GPQA
29
95
SuperGPQA
27
93
OpenBookQA
25
90
MMLU-Pro
54
44
HLE
5
90
FrontierScience
34

Instruction Following

GPT-5.3 Codex

GPT-5.3 Codex

93

Ministral 3 8B (Reasoning)

70

93
IFEval
70

Multilingual

GPT-5.3 Codex

GPT-5.3 Codex

92.8

Ministral 3 8B (Reasoning)

61.7

96
MGSM
63
91
MMLU-ProX
61

Mathematics

GPT-5.3 Codex

GPT-5.3 Codex

97.7

Ministral 3 8B (Reasoning)

47.8

99
AIME 2023
33
99
AIME 2024
35
98
AIME 2025
34
95
HMMT Feb 2023
29
97
HMMT Feb 2024
31
96
HMMT Feb 2025
30
96
BRUMO 2025
32
99
MATH-500
67

Frequently Asked Questions

Which is better, GPT-5.3 Codex or Ministral 3 8B (Reasoning)?

GPT-5.3 Codex is ahead overall, 89 to 36. The biggest single separator in this matchup is SWE-bench Pro, where the scores are 90 and 14.

Which is better for knowledge tasks, GPT-5.3 Codex or Ministral 3 8B (Reasoning)?

GPT-5.3 Codex has the edge for knowledge tasks in this comparison, averaging 80.3 versus 30. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5.3 Codex or Ministral 3 8B (Reasoning)?

GPT-5.3 Codex has the edge for coding in this comparison, averaging 87.3 versus 15.2. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5.3 Codex or Ministral 3 8B (Reasoning)?

GPT-5.3 Codex has the edge for math in this comparison, averaging 97.7 versus 47.8. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-5.3 Codex or Ministral 3 8B (Reasoning)?

GPT-5.3 Codex has the edge for reasoning in this comparison, averaging 93.7 versus 42.1. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-5.3 Codex or Ministral 3 8B (Reasoning)?

GPT-5.3 Codex has the edge for agentic tasks in this comparison, averaging 88.1 versus 38.5. 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 or Ministral 3 8B (Reasoning)?

GPT-5.3 Codex has the edge for multimodal and grounded tasks in this comparison, averaging 91.3 versus 33.4. 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 or Ministral 3 8B (Reasoning)?

GPT-5.3 Codex has the edge for instruction following in this comparison, averaging 93 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 or Ministral 3 8B (Reasoning)?

GPT-5.3 Codex has the edge for multilingual tasks in this comparison, averaging 92.8 versus 61.7. Inside this category, MGSM is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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