Grok 4.1 Fast vs Aion-2.0

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

Grok 4.1 Fast is clearly ahead on the aggregate, 76 to 58. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Grok 4.1 Fast's sharpest advantage is in coding, where it averages 59.5 against 33.2. The single biggest benchmark swing on the page is SWE-bench Verified, 68 to 35. Aion-2.0 does hit back in instruction following, so the answer changes if that is the part of the workload you care about most.

Grok 4.1 Fast gives you the larger context window at 1M, compared with 128K for Aion-2.0.

Quick Verdict

Pick Grok 4.1 Fast if you want the stronger benchmark profile. Aion-2.0 only becomes the better choice if instruction following is the priority.

Agentic

Grok 4.1 Fast

Grok 4.1 Fast

71

Aion-2.0

51.7

74
Terminal-Bench 2.0
48
73
BrowseComp
60
66
OSWorld-Verified
50

Coding

Grok 4.1 Fast

Grok 4.1 Fast

59.5

Aion-2.0

33.2

86
HumanEval
66
68
SWE-bench Verified
35
54
LiveCodeBench
29
63
SWE-bench Pro
37

Multimodal & Grounded

Grok 4.1 Fast

Grok 4.1 Fast

87.4

Aion-2.0

66

91
MMMU-Pro
61
83
OfficeQA Pro
72

Reasoning

Grok 4.1 Fast

Grok 4.1 Fast

88.3

Aion-2.0

70.3

90
SimpleQA
76
88
MuSR
74
87
BBH
76
87
LongBench v2
64
89
MRCRv2
65

Knowledge

Grok 4.1 Fast

Grok 4.1 Fast

69.2

Aion-2.0

54

94
MMLU
78
92
GPQA
77
90
SuperGPQA
75
88
OpenBookQA
75
81
MMLU-Pro
67
20
HLE
5
83
FrontierScience
66

Instruction Following

Aion-2.0

Grok 4.1 Fast

90

Aion-2.0

93

90
IFEval
93

Multilingual

Grok 4.1 Fast

Grok 4.1 Fast

84.8

Aion-2.0

78.1

88
MGSM
80
83
MMLU-ProX
77

Mathematics

Grok 4.1 Fast

Grok 4.1 Fast

92.3

Aion-2.0

72.1

96
AIME 2023
74
98
AIME 2024
76
97
AIME 2025
75
92
HMMT Feb 2023
70
94
HMMT Feb 2024
72
93
HMMT Feb 2025
71
95
BRUMO 2025
73
89
MATH-500
71

Frequently Asked Questions

Which is better, Grok 4.1 Fast or Aion-2.0?

Grok 4.1 Fast is ahead overall, 76 to 58. The biggest single separator in this matchup is SWE-bench Verified, where the scores are 68 and 35.

Which is better for knowledge tasks, Grok 4.1 Fast or Aion-2.0?

Grok 4.1 Fast has the edge for knowledge tasks in this comparison, averaging 69.2 versus 54. Inside this category, FrontierScience is the benchmark that creates the most daylight between them.

Which is better for coding, Grok 4.1 Fast or Aion-2.0?

Grok 4.1 Fast has the edge for coding in this comparison, averaging 59.5 versus 33.2. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.

Which is better for math, Grok 4.1 Fast or Aion-2.0?

Grok 4.1 Fast has the edge for math in this comparison, averaging 92.3 versus 72.1. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, Grok 4.1 Fast or Aion-2.0?

Grok 4.1 Fast has the edge for reasoning in this comparison, averaging 88.3 versus 70.3. Inside this category, MRCRv2 is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, Grok 4.1 Fast or Aion-2.0?

Grok 4.1 Fast has the edge for agentic tasks in this comparison, averaging 71 versus 51.7. 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, Grok 4.1 Fast or Aion-2.0?

Grok 4.1 Fast has the edge for multimodal and grounded tasks in this comparison, averaging 87.4 versus 66. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, Grok 4.1 Fast or Aion-2.0?

Aion-2.0 has the edge for instruction following in this comparison, averaging 93 versus 90. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, Grok 4.1 Fast or Aion-2.0?

Grok 4.1 Fast has the edge for multilingual tasks in this comparison, averaging 84.8 versus 78.1. Inside this category, MGSM is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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