GPT-5.3 Instant vs GLM-5 (Reasoning)

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 78. 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 multimodal & grounded, where it averages 95 against 78.5. The single biggest benchmark swing on the page is MMMU-Pro, 95 to 74.

GLM-5 (Reasoning) gives you the larger context window at 200K, compared with 128K for GPT-5.3 Instant.

Quick Verdict

Pick GPT-5.3 Instant if you want the stronger benchmark profile. GLM-5 (Reasoning) only becomes the better choice if you need the larger 200K context window.

Agentic

GPT-5.3 Instant

GPT-5.3 Instant

82.9

GLM-5 (Reasoning)

78.3

86
Terminal-Bench 2.0
81
82
BrowseComp
80
80
OSWorld-Verified
74

Coding

GPT-5.3 Instant

GPT-5.3 Instant

78.7

GLM-5 (Reasoning)

62.5

88
HumanEval
88
76
SWE-bench Verified
62
75
LiveCodeBench
58
83
SWE-bench Pro
67

Multimodal & Grounded

GPT-5.3 Instant

GPT-5.3 Instant

95

GLM-5 (Reasoning)

78.5

95
MMMU-Pro
74
95
OfficeQA Pro
84

Reasoning

GPT-5.3 Instant

GPT-5.3 Instant

94.2

GLM-5 (Reasoning)

88.9

96
SimpleQA
92
94
MuSR
90
97
BBH
91
92
LongBench v2
86
94
MRCRv2
87

Knowledge

GPT-5.3 Instant

GPT-5.3 Instant

80.8

GLM-5 (Reasoning)

72

99
MMLU
96
98
GPQA
94
96
SuperGPQA
92
94
OpenBookQA
90
89
MMLU-Pro
81
44
HLE
29
92
FrontierScience
83

Instruction Following

GPT-5.3 Instant

GPT-5.3 Instant

96

GLM-5 (Reasoning)

92

96
IFEval
92

Multilingual

GPT-5.3 Instant

GPT-5.3 Instant

93.4

GLM-5 (Reasoning)

86.4

96
MGSM
89
92
MMLU-ProX
85

Mathematics

GPT-5.3 Instant

GPT-5.3 Instant

97.2

GLM-5 (Reasoning)

94.4

99
AIME 2023
98
99
AIME 2024
99
98
AIME 2025
98
95
HMMT Feb 2023
94
97
HMMT Feb 2024
96
96
HMMT Feb 2025
95
96
BRUMO 2025
96
98
MATH-500
92

Frequently Asked Questions

Which is better, GPT-5.3 Instant or GLM-5 (Reasoning)?

GPT-5.3 Instant is ahead overall, 87 to 78. The biggest single separator in this matchup is MMMU-Pro, where the scores are 95 and 74.

Which is better for knowledge tasks, GPT-5.3 Instant or GLM-5 (Reasoning)?

GPT-5.3 Instant has the edge for knowledge tasks in this comparison, averaging 80.8 versus 72. Inside this category, HLE is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5.3 Instant or GLM-5 (Reasoning)?

GPT-5.3 Instant has the edge for coding in this comparison, averaging 78.7 versus 62.5. Inside this category, LiveCodeBench is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5.3 Instant or GLM-5 (Reasoning)?

GPT-5.3 Instant has the edge for math in this comparison, averaging 97.2 versus 94.4. Inside this category, MATH-500 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-5.3 Instant or GLM-5 (Reasoning)?

GPT-5.3 Instant has the edge for reasoning in this comparison, averaging 94.2 versus 88.9. Inside this category, MRCRv2 is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-5.3 Instant or GLM-5 (Reasoning)?

GPT-5.3 Instant has the edge for agentic tasks in this comparison, averaging 82.9 versus 78.3. Inside this category, OSWorld-Verified is the benchmark that creates the most daylight between them.

Which is better for multimodal and grounded tasks, GPT-5.3 Instant or GLM-5 (Reasoning)?

GPT-5.3 Instant has the edge for multimodal and grounded tasks in this comparison, averaging 95 versus 78.5. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-5.3 Instant or GLM-5 (Reasoning)?

GPT-5.3 Instant has the edge for instruction following in this comparison, averaging 96 versus 92. 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 GLM-5 (Reasoning)?

GPT-5.3 Instant has the edge for multilingual tasks in this comparison, averaging 93.4 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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