GPT-5.3-Codex-Spark vs Nemotron Ultra 253B

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

GPT-5.3-Codex-Spark is clearly ahead on the aggregate, 87 to 48. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5.3-Codex-Spark's sharpest advantage is in coding, where it averages 82.3 against 33.7. The single biggest benchmark swing on the page is HumanEval, 91 to 41.

GPT-5.3-Codex-Spark gives you the larger context window at 256K, compared with 32K for Nemotron Ultra 253B.

Quick Verdict

Pick GPT-5.3-Codex-Spark if you want the stronger benchmark profile. Nemotron Ultra 253B only becomes the better choice if its workflow or ecosystem matters more than the raw scoreboard.

Agentic

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

85.6

Nemotron Ultra 253B

46.7

90
Terminal-Bench 2.0
46
82
BrowseComp
50
83
OSWorld-Verified
45

Coding

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

82.3

Nemotron Ultra 253B

33.7

91
HumanEval
41
80
SWE-bench Verified
31
80
LiveCodeBench
30
85
SWE-bench Pro
38

Multimodal & Grounded

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

88.3

Nemotron Ultra 253B

44.7

86
MMMU-Pro
37
91
OfficeQA Pro
54

Reasoning

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

92.7

Nemotron Ultra 253B

53.3

94
SimpleQA
47
92
MuSR
45
97
BBH
77
91
LongBench v2
55
92
MRCRv2
56

Knowledge

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

78.3

Nemotron Ultra 253B

42.4

97
MMLU
49
95
GPQA
48
93
SuperGPQA
46
91
OpenBookQA
44
88
MMLU-Pro
63
42
HLE
11
88
FrontierScience
49

Instruction Following

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

92

Nemotron Ultra 253B

78

92
IFEval
78

Multilingual

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

90.8

Nemotron Ultra 253B

70.1

94
MGSM
74
89
MMLU-ProX
68

Mathematics

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

96.7

Nemotron Ultra 253B

59.7

98
AIME 2023
49
98
AIME 2024
51
97
AIME 2025
50
94
HMMT Feb 2023
45
96
HMMT Feb 2024
47
95
HMMT Feb 2025
46
95
BRUMO 2025
48
98
MATH-500
74

Frequently Asked Questions

Which is better, GPT-5.3-Codex-Spark or Nemotron Ultra 253B?

GPT-5.3-Codex-Spark is ahead overall, 87 to 48. The biggest single separator in this matchup is HumanEval, where the scores are 91 and 41.

Which is better for knowledge tasks, GPT-5.3-Codex-Spark or Nemotron Ultra 253B?

GPT-5.3-Codex-Spark has the edge for knowledge tasks in this comparison, averaging 78.3 versus 42.4. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5.3-Codex-Spark or Nemotron Ultra 253B?

GPT-5.3-Codex-Spark has the edge for coding in this comparison, averaging 82.3 versus 33.7. Inside this category, HumanEval is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5.3-Codex-Spark or Nemotron Ultra 253B?

GPT-5.3-Codex-Spark has the edge for math in this comparison, averaging 96.7 versus 59.7. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-5.3-Codex-Spark or Nemotron Ultra 253B?

GPT-5.3-Codex-Spark has the edge for reasoning in this comparison, averaging 92.7 versus 53.3. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-5.3-Codex-Spark or Nemotron Ultra 253B?

GPT-5.3-Codex-Spark has the edge for agentic tasks in this comparison, averaging 85.6 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, GPT-5.3-Codex-Spark or Nemotron Ultra 253B?

GPT-5.3-Codex-Spark has the edge for multimodal and grounded tasks in this comparison, averaging 88.3 versus 44.7. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-5.3-Codex-Spark or Nemotron Ultra 253B?

GPT-5.3-Codex-Spark has the edge for instruction following in this comparison, averaging 92 versus 78. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, GPT-5.3-Codex-Spark or Nemotron Ultra 253B?

GPT-5.3-Codex-Spark has the edge for multilingual tasks in this comparison, averaging 90.8 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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