Claude 4.1 Opus vs Seed 1.6 Flash

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

Claude 4.1 Opus is clearly ahead on the aggregate, 64 to 56. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Claude 4.1 Opus's sharpest advantage is in coding, where it averages 44 against 27.6. The single biggest benchmark swing on the page is SWE-bench Verified, 48 to 24.

Seed 1.6 Flash is the reasoning model in the pair, while Claude 4.1 Opus 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. Seed 1.6 Flash gives you the larger context window at 256K, compared with 200K for Claude 4.1 Opus.

Quick Verdict

Pick Claude 4.1 Opus if you want the stronger benchmark profile. Seed 1.6 Flash only becomes the better choice if you need the larger 256K context window or you want the stronger reasoning-first profile.

Agentic

Claude 4.1 Opus

Claude 4.1 Opus

58.7

Seed 1.6 Flash

54.5

58
Terminal-Bench 2.0
52
62
BrowseComp
62
57
OSWorld-Verified
52

Coding

Claude 4.1 Opus

Claude 4.1 Opus

44

Seed 1.6 Flash

27.6

68
HumanEval
59
48
SWE-bench Verified
24
40
LiveCodeBench
25
47
SWE-bench Pro
31

Multimodal & Grounded

Claude 4.1 Opus

Claude 4.1 Opus

80.7

Seed 1.6 Flash

73.1

82
MMMU-Pro
74
79
OfficeQA Pro
72

Reasoning

Claude 4.1 Opus

Claude 4.1 Opus

72.9

Seed 1.6 Flash

66.8

74
SimpleQA
61
72
MuSR
59
81
BBH
75
71
LongBench v2
70
71
MRCRv2
74

Knowledge

Claude 4.1 Opus

Claude 4.1 Opus

57.6

Seed 1.6 Flash

47.3

76
MMLU
65
76
GPQA
64
74
SuperGPQA
62
72
OpenBookQA
60
75
MMLU-Pro
65
11
HLE
3
68
FrontierScience
57

Instruction Following

Claude 4.1 Opus

Claude 4.1 Opus

83

Seed 1.6 Flash

81

83
IFEval
81

Multilingual

Claude 4.1 Opus

Claude 4.1 Opus

81.8

Seed 1.6 Flash

72.8

85
MGSM
76
80
MMLU-ProX
71

Mathematics

Claude 4.1 Opus

Claude 4.1 Opus

77.7

Seed 1.6 Flash

67.1

76
AIME 2023
64
78
AIME 2024
66
77
AIME 2025
65
72
HMMT Feb 2023
60
74
HMMT Feb 2024
62
73
HMMT Feb 2025
61
75
BRUMO 2025
63
81
MATH-500
72

Frequently Asked Questions

Which is better, Claude 4.1 Opus or Seed 1.6 Flash?

Claude 4.1 Opus is ahead overall, 64 to 56. The biggest single separator in this matchup is SWE-bench Verified, where the scores are 48 and 24.

Which is better for knowledge tasks, Claude 4.1 Opus or Seed 1.6 Flash?

Claude 4.1 Opus has the edge for knowledge tasks in this comparison, averaging 57.6 versus 47.3. Inside this category, GPQA is the benchmark that creates the most daylight between them.

Which is better for coding, Claude 4.1 Opus or Seed 1.6 Flash?

Claude 4.1 Opus has the edge for coding in this comparison, averaging 44 versus 27.6. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.

Which is better for math, Claude 4.1 Opus or Seed 1.6 Flash?

Claude 4.1 Opus has the edge for math in this comparison, averaging 77.7 versus 67.1. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, Claude 4.1 Opus or Seed 1.6 Flash?

Claude 4.1 Opus has the edge for reasoning in this comparison, averaging 72.9 versus 66.8. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, Claude 4.1 Opus or Seed 1.6 Flash?

Claude 4.1 Opus has the edge for agentic tasks in this comparison, averaging 58.7 versus 54.5. 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, Claude 4.1 Opus or Seed 1.6 Flash?

Claude 4.1 Opus has the edge for multimodal and grounded tasks in this comparison, averaging 80.7 versus 73.1. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, Claude 4.1 Opus or Seed 1.6 Flash?

Claude 4.1 Opus has the edge for instruction following in this comparison, averaging 83 versus 81. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, Claude 4.1 Opus or Seed 1.6 Flash?

Claude 4.1 Opus has the edge for multilingual tasks in this comparison, averaging 81.8 versus 72.8. Inside this category, MGSM is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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