Model comparison
gpt-oss-20b vs Nemotron 3.5 Lightning
Nemotron 3.5 Lightning is the stronger model overall, scoring 40.0 to 32.5 on the Noometry Index. gpt-oss-20b costs 2.4× less per token, which makes it the better buy when Nemotron 3.5 Lightning's lead doesn't matter for your workload.
Last verified . 17 shared benchmarks.
NVIDIASummary
- They share 17 benchmarks with published results for both. gpt-oss-20b scores higher in 1 category and Nemotron 3.5 Lightning in 7 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in writing & preference, where Nemotron 3.5 Lightning leads 48.5 to 35.5.
- gpt-oss-20b is cheaper at $0.018 / $0.09 per million input/output tokens, against $0.05 / $0.20 for Nemotron 3.5 Lightning.
- Nemotron 3.5 Lightning accepts more context: 262K tokens versus 131K.
Side by side
| gpt-oss-20b | Nemotron 3.5 Lightning | |
|---|---|---|
| Provider | OpenAI | NVIDIA |
| Noometry Index | 32.5 | 40.0 |
| Released | 2025-08-05 | 2026-08-11 |
| Weights | Open | Open |
| Context window | 131K | 262K |
| Max output | 16K | 262K |
| Input $ / M tokens | $0.018 | $0.05 |
| Output $ / M tokens | $0.09 | $0.20 |
| Results tracked | 34 | 18 |
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Category by category
Coding Nemotron 3.5 Lightning leads
gpt-oss-20b: 37.6 (#192), Nemotron 3.5 Lightning: 40.4 (#141)
| Benchmark | gpt-oss-20b | Nemotron 3.5 Lightning |
|---|---|---|
| LMArena Coding | 1306 | 1375 |
| SciCode | 34.4% | — |
| WeirdML | 40.9% | — |
| ALE-Bench | 566.05 | — |
Agentic & Tool Use Not comparable
gpt-oss-20b: 9.3 (#154), Nemotron 3.5 Lightning: —
| Benchmark | gpt-oss-20b | Nemotron 3.5 Lightning |
|---|---|---|
| Terminal-Bench | 3.4% | — |
Reasoning Nemotron 3.5 Lightning leads
gpt-oss-20b: 19.3 (#261), Nemotron 3.5 Lightning: 26.8 (#127)
| Benchmark | gpt-oss-20b | Nemotron 3.5 Lightning |
|---|---|---|
| LMArena Hard Prompts | 1274 | 1337 |
| Kagi LLM Benchmark | 53.2% | — |
| CritPt | 1.4% | — |
| Chess Puzzles | 4% | — |
| DTBench | 68% | — |
| LMCA | 14.5% | — |
| Epoch Capabilities Index | 137.82 | — |
Math gpt-oss-20b leads
gpt-oss-20b: 39.4 (#103), Nemotron 3.5 Lightning: 37.5 (#155)
| Benchmark | gpt-oss-20b | Nemotron 3.5 Lightning |
|---|---|---|
| LMArena Math | 1317 | 1359 |
| OTIS Mock AIME 2024-2025 | 65.3% | — |
| Omni-MATH | 56.5% | — |
Knowledge Nemotron 3.5 Lightning leads
gpt-oss-20b: 34.6 (#195), Nemotron 3.5 Lightning: 37.5 (#154)
| Benchmark | gpt-oss-20b | Nemotron 3.5 Lightning |
|---|---|---|
| LMArena Expert | 1258 | 1356 |
| GPQA Diamond | 60.8% | — |
| MMLU-Pro | 74% | — |
| GPQA (HELM) | 59.4% | — |
Multilingual Nemotron 3.5 Lightning leads
gpt-oss-20b: 42.2 (#197), Nemotron 3.5 Lightning: 44.0 (#180)
| Benchmark | gpt-oss-20b | Nemotron 3.5 Lightning |
|---|---|---|
| LMArena Non-English | 1268 | 1295 |
| LMArena Chinese | 1314 | 1359 |
| LMArena German | 1255 | 1282 |
| LMArena Japanese | 1244 | 1206 |
| LMArena Korean | 1236 | 1238 |
| LMArena Russian | 1278 | 1253 |
| LMArena Spanish | 1267 | 1345 |
| LMArena French | — | 1366 |
Instruction Following Nemotron 3.5 Lightning leads
gpt-oss-20b: 61.8 (#240), Nemotron 3.5 Lightning: 69.6 (#170)
| Benchmark | gpt-oss-20b | Nemotron 3.5 Lightning |
|---|---|---|
| LMArena Instruction Following | 1236 | 1318 |
| IFEval | 73.2% | — |
Long Context Nemotron 3.5 Lightning leads
gpt-oss-20b: 37.9 (#209), Nemotron 3.5 Lightning: 39.9 (#165)
| Benchmark | gpt-oss-20b | Nemotron 3.5 Lightning |
|---|---|---|
| LMArena Longer Query | 1250 | 1314 |
Writing & Preference Nemotron 3.5 Lightning leads
gpt-oss-20b: 35.5 (#265), Nemotron 3.5 Lightning: 48.5 (#201)
| Benchmark | gpt-oss-20b | Nemotron 3.5 Lightning |
|---|---|---|
| LMArena Text | 1287 | 1327 |
| LMArena Creative Writing | 1201 | 1254 |
| EQ-Bench Creative Writing | 666 | 1280 |
| LMArena Multi-Turn | 1268 | 1328 |
| WildBench | 73.7% | — |
Frequently asked questions
Is gpt-oss-20b better than Nemotron 3.5 Lightning?
Nemotron 3.5 Lightning is the stronger model overall, scoring 40.0 to 32.5 on the Noometry Index. gpt-oss-20b costs 2.4× less per token, which makes it the better buy when Nemotron 3.5 Lightning's lead doesn't matter for your workload.
Which is cheaper, gpt-oss-20b or Nemotron 3.5 Lightning?
gpt-oss-20b is cheaper. It lists at $0.018 per million input tokens and $0.09 per million output tokens; Nemotron 3.5 Lightning lists at $0.05 and $0.20.
Is gpt-oss-20b or Nemotron 3.5 Lightning better for coding?
Nemotron 3.5 Lightning scores higher on coding benchmarks: 40.4 versus 37.6 in the Noometry coding category.
Which has the bigger context window?
Nemotron 3.5 Lightning does, with 262K tokens against 131K.
How many benchmarks do gpt-oss-20b and Nemotron 3.5 Lightning share?
17 benchmarks have published results for both models. gpt-oss-20b has 34 scored results on Noometry and Nemotron 3.5 Lightning has 18.