Model comparison
GPT-5.3 Codex vs Nemotron 3 Ultra
Head-to-head evidence from 15 shared benchmark results across 6 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Verified leaderboard positions: GPT-5.3 Codex unranked; Nemotron 3 Ultra #24
BenchAlign evidence: GPT-5.3 Codex supported; Nemotron 3 Ultra not scored. Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. GPT-5.3 Codex and Nemotron 3 Ultra share 15 comparable benchmark results. 2 of 8 categories are comparable. 7 results are unique to GPT-5.3 Codex; 24 to Nemotron 3 Ultra.
Updated July 16, 2026- Shared results
- 15
- GPT-5.3 Codex only
- 7
- Nemotron 3 Ultra only
- 24
- Comparable categories
- 2 / 8
Pick GPT-5.3 Codex if you want the stronger benchmark profile. Nemotron 3 Ultra only becomes the better choice if you want the cheaper token bill or you need the larger 1M context window.
Confidence note. This is a partial-evidence comparison with 15 shared benchmark results across 6 evidence categories; 2 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
GPT-5.3 Codex is clearly ahead on the provisional aggregate, 82 to 60. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.3 Codex's sharpest advantage is in agentic, where it averages 71.4 against 51.3. The single biggest benchmark swing on the page is Terminal-Bench 2.0, 77.3% to 56.4%.
GPT-5.3 Codex is also the more expensive model on tokens at $1.75 input / $14.00 output per 1M tokens, versus $0.00 input / $0.00 output per 1M tokens for Nemotron 3 Ultra. That is roughly Infinityx on output cost alone. Nemotron 3 Ultra gives you the larger context window at 1M, compared with 400K for GPT-5.3 Codex.
Category breakdown
Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.
| Category | GPT-5.3 Codex | Δ | Nemotron 3 Ultra |
|---|---|---|---|
| Agentic | GPT-5.3 Codex71.4 | Margin← 20.1 | Nemotron 3 Ultra51.3 |
| Coding | GPT-5.3 Codex67.2 | Margin← 8.9 | Nemotron 3 Ultra58.3 |
| Reasoning | GPT-5.3 CodexNot measured | MarginNo overlap | Nemotron 3 Ultra61.9 |
| Knowledge | GPT-5.3 CodexNot measured | MarginNo overlap | Nemotron 3 Ultra54.2 |
| Multilingual | GPT-5.3 CodexNot measured | MarginNo overlap | Nemotron 3 Ultra83.0 |
| Inst. Following | GPT-5.3 CodexNot measured | MarginNo overlap | Nemotron 3 Ultra81.7 |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
Terminal-Bench 2.0
AgenticA 77.3%B 56.4%Winner: GPT-5.3 CodexΔ 20.9Terminal-Bench 2.0: GPT-5.3 Codex scored 77.3%; Nemotron 3 Ultra scored 56.4%. GPT-5.3 Codex wins this benchmark. - Source ↗
SWE-bench Verified
CodingA 85%B 71.9%Winner: GPT-5.3 CodexΔ 13.1SWE-bench Verified: GPT-5.3 Codex scored 85%; Nemotron 3 Ultra scored 71.9%. GPT-5.3 Codex wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | GPT-5.3 Codex | Nemotron 3 Ultra | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | GPT-5.3 Codex$1.75 input / $14 output | Nemotron 3 Ultra$0 input / $0 output | Nemotron 3 Ultra has the lower combined listed price. |
| Generation speedtokens per second | GPT-5.3 Codex79 tok/s | Nemotron 3 UltraNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | GPT-5.3 Codex88.26 s | Nemotron 3 UltraNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | GPT-5.3 Codex400K | Nemotron 3 Ultra1M | Nemotron 3 Ultra lists the larger context window. |
Benchmark Deep Dive
AgenticGPT-5.3 Codex wins15 benchmarks
| Benchmark | GPT-5.3 Codex | Nemotron 3 Ultra | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 77.3% | 56.4% | GPT-5.3 Codex leads |
| OSWorld-VerifiedSource | 64.7% | — | Not comparable |
| τ²-bench resultsSource | 86% | 83.3% | GPT-5.3 Codex leads |
| Gert LabsSource | 57.47% | — | Not comparable |
| JobBenchSource | 33.7% | — | Not comparable |
| PinchBenchSource | — | 90.0% | Not comparable |
| BrowseCompSource | — | 44.4% | Not comparable |
| τ³-bench resultsSource | — | 70.9% | Not comparable |
| GDPval-AASource | — | 33.2% | Not comparable |
| HLE w/ toolsSource | — | 37.4% | Not comparable |
| AA Agentic IndexSource | — | 27.4% | Not comparable |
| GDPval-AASource | — | 1164 | Not comparable |
| AA BriefcaseSource | — | 870 | Not comparable |
| AA EnterpriseOps-GymSource | — | 28.9% | Not comparable |
| AA Harvey LABSource | — | 3.3% | Not comparable |
CodingGPT-5.3 Codex wins11 benchmarks
| Benchmark | GPT-5.3 Codex | Nemotron 3 Ultra | Result |
|---|---|---|---|
| SWE-bench VerifiedSource | 85% | 71.9% | GPT-5.3 Codex leads |
| SWE-bench ProSource | 56.8% | — | Not comparable |
| SWE-RebenchSource | 58.2% | — | Not comparable |
| Vibe Code BenchSource | 61.77% | — | Not comparable |
| Terminal-Bench HardSource | 53.0% | 36.4% | GPT-5.3 Codex leads |
| AA-SciCodeSource | 53.2% | 39.9% | GPT-5.3 Codex leads |
| SWE MultilingualSource | — | 67.7% | Not comparable |
| LiveCodeBench v6Source | — | 89.0% | Not comparable |
| SciCodeSource | — | 44.6% | Not comparable |
| Terminal-Bench 2.0Source | — | 56.4% | Not comparable |
| AA Coding IndexSource | — | 49.3% | Not comparable |
Reasoning3 benchmarks
Knowledge12 benchmarks
| Benchmark | GPT-5.3 Codex | Nemotron 3 Ultra | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | 44.3% | 37.8% | GPT-5.3 Codex leads |
| AA-GPQA DiamondSource | 91.5% | 86.7% | GPT-5.3 Codex leads |
| AA-HLESource | 39.9% | 26.6% | GPT-5.3 Codex leads |
| AA-Omniscience IndexSource | 9.9% | -0.8% | GPT-5.3 Codex leads |
| AA-Omniscience AccuracySource | 51.8% | 21.6% | GPT-5.3 Codex leads |
| AA-Omniscience Hallucination RateSource | 86.9% | 28.5% | Nemotron 3 Ultra leads |
| GPQASource | — | 87% | Not comparable |
| GPQA-DSource | — | 87.0% | Not comparable |
| HLESource | — | 26.7% | Not comparable |
| HLE w/o toolsSource | — | 26.7% | Not comparable |
| MMLU-ProSource | — | 86.8% | Not comparable |
| AA Openness IndexSource | — | 83.3% | Not comparable |
Multilingual1 benchmarks
| Benchmark | GPT-5.3 Codex | Nemotron 3 Ultra | Result |
|---|---|---|---|
| MMLU-ProXSource | — | 83% | Not comparable |
Multimodal2 benchmarks
Frequently Asked Questions (3)
Which is better, GPT-5.3 Codex or Nemotron 3 Ultra?
GPT-5.3 Codex is ahead on BenchLM's provisional leaderboard, 82 to 60. The biggest single separator in this matchup is Terminal-Bench 2.0, where the scores are 77.3% and 56.4%.
Which is better for coding, GPT-5.3 Codex or Nemotron 3 Ultra?
GPT-5.3 Codex has the edge for coding in this comparison, averaging 67.2 versus 58.3. Inside this category, Terminal-Bench Hard is the benchmark that creates the most daylight between them.
Which is better for agentic tasks, GPT-5.3 Codex or Nemotron 3 Ultra?
GPT-5.3 Codex has the edge for agentic tasks in this comparison, averaging 71.4 versus 51.3. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.
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