Model comparison

GPT-5.1-Codex vs Nemotron 3 Ultra

Nemotron 3 Ultra is the stronger model overall, scoring 44.7 to 38.2 on the Noometry Index.

Last verified . 1 shared benchmarks.

GPT-5.1-Codex OpenAI

38.2

Rank #178 Reported

Nemotron 3 Ultra NVIDIA

44.7

Rank #71 Confirmed

Summary

  • They share 1 benchmark with published results for both. GPT-5.1-Codex scores higher in 1 category and Nemotron 3 Ultra in 1 category; 2 gaps are clear of the uncertainty.
  • The widest gap is in math, where Nemotron 3 Ultra leads 34.4 to 29.3.
  • The biggest single-benchmark swing is ProofBench: 9% for GPT-5.1-Codex and 2% for Nemotron 3 Ultra.
  • Nemotron 3 Ultra is cheaper at $0.60 / $2.40 per million input/output tokens, against $1.25 / $10 for GPT-5.1-Codex.
  • GPT-5.1-Codex accepts more context: 400K tokens versus 262K.
  • Nemotron 3 Ultra has downloadable open weights; the other is API-only.

Side by side

GPT-5.1-Codex and Nemotron 3 Ultra specifications
GPT-5.1-CodexNemotron 3 Ultra
ProviderOpenAINVIDIA
Noometry Index38.244.7
Released2025-11-122026-06-04
WeightsProprietaryOpen
Context window400K262K
Max output128K128K
Input $ / M tokens$1.25$0.60
Output $ / M tokens$10$2.40
Results tracked629

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Category by category

Coding GPT-5.1-Codex leads

GPT-5.1-Codex: 41.7 (#107), Nemotron 3 Ultra: 37.7 (#174)

Coding benchmarks
BenchmarkGPT-5.1-CodexNemotron 3 Ultra
FrontierCode—13.6%
SWE-bench Verified (bash only)66%—
LMArena WebDev1337—
SciCode—40.3%
WeirdML—43.5%
LMArena Coding—1468
ALE-Bench1,245—

Agentic & Tool Use Not comparable

GPT-5.1-Codex: 37.8 (#32), Nemotron 3 Ultra: —

Agentic & Tool Use benchmarks
BenchmarkGPT-5.1-CodexNemotron 3 Ultra
Terminal-Bench60.4%—
METR Time Horizons70.8%—

Reasoning Not comparable

GPT-5.1-Codex: —, Nemotron 3 Ultra: 30.3 (#78)

Reasoning benchmarks
BenchmarkGPT-5.1-CodexNemotron 3 Ultra
CritPt—3.1%
Chess Puzzles—12%
LMArena Hard Prompts—1452
Mystery Game Puzzles—20%
DTBench—90.1%
LMCA—36.9%
Epoch Capabilities Index—146.2

Math Nemotron 3 Ultra leads

GPT-5.1-Codex: 29.3 (#218), Nemotron 3 Ultra: 34.4 (#160)

Math benchmarks
BenchmarkGPT-5.1-CodexNemotron 3 Ultra
ProofBench9%2%
OTIS Mock AIME 2024-2025—86.7%
LMArena Math—1456

Knowledge Not comparable

GPT-5.1-Codex: —, Nemotron 3 Ultra: 52.5 (#56)

Knowledge benchmarks
BenchmarkGPT-5.1-CodexNemotron 3 Ultra
GPQA Diamond—85.4%
LMArena Expert—1472

Multilingual Not comparable

GPT-5.1-Codex: —, Nemotron 3 Ultra: 53.7 (#61)

Multilingual benchmarks
BenchmarkGPT-5.1-CodexNemotron 3 Ultra
LMArena Non-English—1427
LMArena Chinese—1498
LMArena French—1475
LMArena German—1471
LMArena Korean—1387
LMArena Russian—1415
LMArena Spanish—1452

Instruction Following Not comparable

GPT-5.1-Codex: —, Nemotron 3 Ultra: 74.9 (#84)

Instruction Following benchmarks
BenchmarkGPT-5.1-CodexNemotron 3 Ultra
LMArena Instruction Following—1417

Long Context Not comparable

GPT-5.1-Codex: —, Nemotron 3 Ultra: 43.9 (#77)

Long Context benchmarks
BenchmarkGPT-5.1-CodexNemotron 3 Ultra
LMArena Longer Query—1437

Writing & Preference Not comparable

GPT-5.1-Codex: —, Nemotron 3 Ultra: 66.3 (#35)

Writing & Preference benchmarks
BenchmarkGPT-5.1-CodexNemotron 3 Ultra
LMArena Text—1444
LMArena Creative Writing—1392
EQ-Bench Creative Writing—1692
LMArena Multi-Turn—1412

Frequently asked questions

Is GPT-5.1-Codex better than Nemotron 3 Ultra?

Nemotron 3 Ultra is the stronger model overall, scoring 44.7 to 38.2 on the Noometry Index.

Which is cheaper, GPT-5.1-Codex or Nemotron 3 Ultra?

Nemotron 3 Ultra is cheaper. It lists at $0.60 per million input tokens and $2.40 per million output tokens; GPT-5.1-Codex lists at $1.25 and $10.

Is GPT-5.1-Codex or Nemotron 3 Ultra better for coding?

GPT-5.1-Codex scores higher on coding benchmarks: 41.7 versus 37.7 in the Noometry coding category.

Which has the bigger context window?

GPT-5.1-Codex does, with 400K tokens against 262K.

How many benchmarks do GPT-5.1-Codex and Nemotron 3 Ultra share?

1 benchmark has published results for both models. GPT-5.1-Codex has 6 scored results on Noometry and Nemotron 3 Ultra has 29.

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