GPT-5.1-Codex-Max vs Seed-2.0-Lite

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

GPT-5.1-Codex-Max is clearly ahead on the aggregate, 84 to 63. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5.1-Codex-Max's sharpest advantage is in coding, where it averages 75.5 against 41.4. The single biggest benchmark swing on the page is SWE-bench Pro, 84 to 45.

GPT-5.1-Codex-Max is also the more expensive model on tokens at $2.00 input / $8.00 output per 1M tokens, versus $0.25 input / $2.00 output per 1M tokens for Seed-2.0-Lite. That is roughly 4.0x on output cost alone. GPT-5.1-Codex-Max is the reasoning model in the pair, while Seed-2.0-Lite 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-5.1-Codex-Max gives you the larger context window at 400K, compared with 256K for Seed-2.0-Lite.

Quick Verdict

Pick GPT-5.1-Codex-Max if you want the stronger benchmark profile. Seed-2.0-Lite only becomes the better choice if you want the cheaper token bill or you would rather avoid the extra latency and token burn of a reasoning model.

Agentic

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

86

Seed-2.0-Lite

55.1

90
Terminal-Bench 2.0
52
85
BrowseComp
63
82
OSWorld-Verified
53

Coding

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

75.5

Seed-2.0-Lite

41.4

94
HumanEval
63
75
SWE-bench Verified
45
67
LiveCodeBench
37
84
SWE-bench Pro
45

Multimodal & Grounded

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

88.2

Seed-2.0-Lite

79.6

85
MMMU-Pro
80
92
OfficeQA Pro
79

Reasoning

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

92.1

Seed-2.0-Lite

73

94
SimpleQA
68
92
MuSR
66
92
BBH
85
90
LongBench v2
76
93
MRCRv2
77

Knowledge

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

72.6

Seed-2.0-Lite

53.9

98
MMLU
71
96
GPQA
70
94
SuperGPQA
68
92
OpenBookQA
66
82
MMLU-Pro
73
27
HLE
7
84
FrontierScience
66

Instruction Following

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

91

Seed-2.0-Lite

89

91
IFEval
89

Multilingual

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

87.7

Seed-2.0-Lite

82.5

89
MGSM
87
87
MMLU-ProX
80

Mathematics

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

94.9

Seed-2.0-Lite

75

99
AIME 2023
71
99
AIME 2024
73
98
AIME 2025
72
95
HMMT Feb 2023
67
97
HMMT Feb 2024
69
96
HMMT Feb 2025
68
96
BRUMO 2025
70
93
MATH-500
81

Frequently Asked Questions

Which is better, GPT-5.1-Codex-Max or Seed-2.0-Lite?

GPT-5.1-Codex-Max is ahead overall, 84 to 63. The biggest single separator in this matchup is SWE-bench Pro, where the scores are 84 and 45.

Which is better for knowledge tasks, GPT-5.1-Codex-Max or Seed-2.0-Lite?

GPT-5.1-Codex-Max has the edge for knowledge tasks in this comparison, averaging 72.6 versus 53.9. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5.1-Codex-Max or Seed-2.0-Lite?

GPT-5.1-Codex-Max has the edge for coding in this comparison, averaging 75.5 versus 41.4. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5.1-Codex-Max or Seed-2.0-Lite?

GPT-5.1-Codex-Max has the edge for math in this comparison, averaging 94.9 versus 75. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-5.1-Codex-Max or Seed-2.0-Lite?

GPT-5.1-Codex-Max has the edge for reasoning in this comparison, averaging 92.1 versus 73. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-5.1-Codex-Max or Seed-2.0-Lite?

GPT-5.1-Codex-Max has the edge for agentic tasks in this comparison, averaging 86 versus 55.1. 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-5.1-Codex-Max or Seed-2.0-Lite?

GPT-5.1-Codex-Max has the edge for multimodal and grounded tasks in this comparison, averaging 88.2 versus 79.6. Inside this category, OfficeQA Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-5.1-Codex-Max or Seed-2.0-Lite?

GPT-5.1-Codex-Max has the edge for instruction following in this comparison, averaging 91 versus 89. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, GPT-5.1-Codex-Max or Seed-2.0-Lite?

GPT-5.1-Codex-Max has the edge for multilingual tasks in this comparison, averaging 87.7 versus 82.5. Inside this category, MMLU-ProX is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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