GPT-5.3 Instant vs Gemma 3 27B

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

GPT-5.3 Instant is clearly ahead on the aggregate, 87 to 38. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5.3 Instant's sharpest advantage is in coding, where it averages 78.7 against 16. The single biggest benchmark swing on the page is SWE-bench Pro, 83 to 17.

GPT-5.3 Instant is the reasoning model in the pair, while Gemma 3 27B 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. GPT-5.3 Instant gives you the larger context window at 128K, compared with 32K for Gemma 3 27B.

Quick Verdict

Pick GPT-5.3 Instant if you want the stronger benchmark profile. Gemma 3 27B only becomes the better choice if you would rather avoid the extra latency and token burn of a reasoning model.

Agentic

GPT-5.3 Instant

GPT-5.3 Instant

82.9

Gemma 3 27B

34.4

86
Terminal-Bench 2.0
29
82
BrowseComp
42
80
OSWorld-Verified
35

Coding

GPT-5.3 Instant

GPT-5.3 Instant

78.7

Gemma 3 27B

16

88
HumanEval
37
76
SWE-bench Verified
16
75
LiveCodeBench
15
83
SWE-bench Pro
17

Multimodal & Grounded

GPT-5.3 Instant

GPT-5.3 Instant

95

Gemma 3 27B

41.7

95
MMMU-Pro
39
95
OfficeQA Pro
45

Reasoning

GPT-5.3 Instant

GPT-5.3 Instant

94.2

Gemma 3 27B

45.6

96
SimpleQA
43
94
MuSR
41
97
BBH
62
92
LongBench v2
47
94
MRCRv2
44

Knowledge

GPT-5.3 Instant

GPT-5.3 Instant

80.8

Gemma 3 27B

34.6

99
MMLU
45
98
GPQA
44
96
SuperGPQA
42
94
OpenBookQA
40
89
MMLU-Pro
50
44
HLE
3
92
FrontierScience
42

Instruction Following

GPT-5.3 Instant

GPT-5.3 Instant

96

Gemma 3 27B

67

96
IFEval
67

Multilingual

GPT-5.3 Instant

GPT-5.3 Instant

93.4

Gemma 3 27B

61.4

96
MGSM
64
92
MMLU-ProX
60

Mathematics

GPT-5.3 Instant

GPT-5.3 Instant

97.2

Gemma 3 27B

49.4

99
AIME 2023
45
99
AIME 2024
47
98
AIME 2025
46
95
HMMT Feb 2023
41
97
HMMT Feb 2024
43
96
HMMT Feb 2025
42
96
BRUMO 2025
44
98
MATH-500
56

Frequently Asked Questions

Which is better, GPT-5.3 Instant or Gemma 3 27B?

GPT-5.3 Instant is ahead overall, 87 to 38. The biggest single separator in this matchup is SWE-bench Pro, where the scores are 83 and 17.

Which is better for knowledge tasks, GPT-5.3 Instant or Gemma 3 27B?

GPT-5.3 Instant has the edge for knowledge tasks in this comparison, averaging 80.8 versus 34.6. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5.3 Instant or Gemma 3 27B?

GPT-5.3 Instant has the edge for coding in this comparison, averaging 78.7 versus 16. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5.3 Instant or Gemma 3 27B?

GPT-5.3 Instant has the edge for math in this comparison, averaging 97.2 versus 49.4. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-5.3 Instant or Gemma 3 27B?

GPT-5.3 Instant has the edge for reasoning in this comparison, averaging 94.2 versus 45.6. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-5.3 Instant or Gemma 3 27B?

GPT-5.3 Instant has the edge for agentic tasks in this comparison, averaging 82.9 versus 34.4. 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 Instant or Gemma 3 27B?

GPT-5.3 Instant has the edge for multimodal and grounded tasks in this comparison, averaging 95 versus 41.7. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-5.3 Instant or Gemma 3 27B?

GPT-5.3 Instant has the edge for instruction following in this comparison, averaging 96 versus 67. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, GPT-5.3 Instant or Gemma 3 27B?

GPT-5.3 Instant has the edge for multilingual tasks in this comparison, averaging 93.4 versus 61.4. Inside this category, MGSM is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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