Step 3.5 Flash vs Nemotron Ultra 253B

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

Step 3.5 Flash is clearly ahead on the aggregate, 66 to 48. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Step 3.5 Flash's sharpest advantage is in reasoning, where it averages 78.3 against 53.3. The single biggest benchmark swing on the page is MuSR, 82 to 45.

Nemotron Ultra 253B is the reasoning model in the pair, while Step 3.5 Flash 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. Step 3.5 Flash gives you the larger context window at 256K, compared with 32K for Nemotron Ultra 253B.

Quick Verdict

Pick Step 3.5 Flash if you want the stronger benchmark profile. Nemotron Ultra 253B only becomes the better choice if you want the stronger reasoning-first profile.

Agentic

Step 3.5 Flash

Step 3.5 Flash

60.2

Nemotron Ultra 253B

46.7

62
Terminal-Bench 2.0
46
66
BrowseComp
50
54
OSWorld-Verified
45

Coding

Step 3.5 Flash

Step 3.5 Flash

47.1

Nemotron Ultra 253B

33.7

77
HumanEval
41
48
SWE-bench Verified
31
45
LiveCodeBench
30
49
SWE-bench Pro
38

Multimodal & Grounded

Step 3.5 Flash

Step 3.5 Flash

66.7

Nemotron Ultra 253B

44.7

64
MMMU-Pro
37
70
OfficeQA Pro
54

Reasoning

Step 3.5 Flash

Step 3.5 Flash

78.3

Nemotron Ultra 253B

53.3

82
SimpleQA
47
82
MuSR
45
83
BBH
77
74
LongBench v2
55
73
MRCRv2
56

Knowledge

Step 3.5 Flash

Step 3.5 Flash

60.8

Nemotron Ultra 253B

42.4

84
MMLU
49
83
GPQA
48
81
SuperGPQA
46
79
OpenBookQA
44
76
MMLU-Pro
63
12
HLE
11
71
FrontierScience
49

Instruction Following

Step 3.5 Flash

Step 3.5 Flash

87

Nemotron Ultra 253B

78

87
IFEval
78

Multilingual

Step 3.5 Flash

Step 3.5 Flash

82.8

Nemotron Ultra 253B

70.1

86
MGSM
74
81
MMLU-ProX
68

Mathematics

Step 3.5 Flash

Step 3.5 Flash

84.5

Nemotron Ultra 253B

59.7

85
AIME 2023
49
87
AIME 2024
51
86
AIME 2025
50
81
HMMT Feb 2023
45
83
HMMT Feb 2024
47
82
HMMT Feb 2025
46
84
BRUMO 2025
48
85
MATH-500
74

Frequently Asked Questions

Which is better, Step 3.5 Flash or Nemotron Ultra 253B?

Step 3.5 Flash is ahead overall, 66 to 48. The biggest single separator in this matchup is MuSR, where the scores are 82 and 45.

Which is better for knowledge tasks, Step 3.5 Flash or Nemotron Ultra 253B?

Step 3.5 Flash has the edge for knowledge tasks in this comparison, averaging 60.8 versus 42.4. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, Step 3.5 Flash or Nemotron Ultra 253B?

Step 3.5 Flash has the edge for coding in this comparison, averaging 47.1 versus 33.7. Inside this category, HumanEval is the benchmark that creates the most daylight between them.

Which is better for math, Step 3.5 Flash or Nemotron Ultra 253B?

Step 3.5 Flash has the edge for math in this comparison, averaging 84.5 versus 59.7. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, Step 3.5 Flash or Nemotron Ultra 253B?

Step 3.5 Flash has the edge for reasoning in this comparison, averaging 78.3 versus 53.3. Inside this category, MuSR is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, Step 3.5 Flash or Nemotron Ultra 253B?

Step 3.5 Flash has the edge for agentic tasks in this comparison, averaging 60.2 versus 46.7. 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, Step 3.5 Flash or Nemotron Ultra 253B?

Step 3.5 Flash has the edge for multimodal and grounded tasks in this comparison, averaging 66.7 versus 44.7. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, Step 3.5 Flash or Nemotron Ultra 253B?

Step 3.5 Flash has the edge for instruction following in this comparison, averaging 87 versus 78. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, Step 3.5 Flash or Nemotron Ultra 253B?

Step 3.5 Flash has the edge for multilingual tasks in this comparison, averaging 82.8 versus 70.1. Inside this category, MMLU-ProX is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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