Model comparison
Grok 4 Fast vs Nemotron 3.5 Lightning
Grok 4 Fast and Nemotron 3.5 Lightning score almost the same on the Noometry Index (39.0 vs 39.3), so choose on price, context window or the category you care about most.
Last verified . 17 shared benchmarks.
NVIDIASummary
- They share 17 benchmarks with published results for both. Grok 4 Fast scores higher in 5 categories and Nemotron 3.5 Lightning in 3 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in long context, where Grok 4 Fast leads 63.2 to 39.9.
- Nemotron 3.5 Lightning has downloadable open weights; the other is API-only.
Side by side
| Grok 4 Fast | Nemotron 3.5 Lightning | |
|---|---|---|
| Provider | xAI | NVIDIA |
| Noometry Index | 39.0 | 39.3 |
| Released | 2025-09-19 | 2026-08-11 |
| Weights | Proprietary | Open |
| Context window | — | 262K |
| Max output | — | 262K |
| Input $ / M tokens | — | $0.06 |
| Output $ / M tokens | — | $0.16 |
| Results tracked | 30 | 18 |
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Category by category
Coding Nemotron 3.5 Lightning leads
Grok 4 Fast: 32.3 (#264), Nemotron 3.5 Lightning: 39.6 (#143)
| Benchmark | Grok 4 Fast | Nemotron 3.5 Lightning |
|---|---|---|
| LMArena Coding | 1429 | 1370 |
| LMArena WebDev | 1160 | — |
| WeirdML | 42.9% | — |
Agentic & Tool Use Not comparable
Grok 4 Fast: 29.3 (#80), Nemotron 3.5 Lightning: —
| Benchmark | Grok 4 Fast | Nemotron 3.5 Lightning |
|---|---|---|
| τ²-bench Banking | 15.7% | — |
| Cybench | 30% | — |
| LMArena Search | 1171 | — |
Reasoning Nemotron 3.5 Lightning leads
Grok 4 Fast: 22.5 (#179), Nemotron 3.5 Lightning: 25.7 (#128)
| Benchmark | Grok 4 Fast | Nemotron 3.5 Lightning |
|---|---|---|
| LMArena Hard Prompts | 1413 | 1335 |
| ARC-AGI-2 | 5.3% | — |
| Kagi LLM Benchmark | 66.1% | — |
| ARC-AGI-1 | 48.5% | — |
| DTBench | 82.7% | — |
| Epoch Capabilities Index | 144.21 | — |
| ForecastBench | 60.5 | — |
Math Grok 4 Fast leads
Grok 4 Fast: 36.1 (#126), Nemotron 3.5 Lightning: 34.7 (#156)
| Benchmark | Grok 4 Fast | Nemotron 3.5 Lightning |
|---|---|---|
| LMArena Math | 1419 | 1355 |
Knowledge Nemotron 3.5 Lightning leads
Grok 4 Fast: 31.5 (#211), Nemotron 3.5 Lightning: 36.9 (#154)
| Benchmark | Grok 4 Fast | Nemotron 3.5 Lightning |
|---|---|---|
| LMArena Expert | 1411 | 1354 |
| Vectara Hallucination Rate | 19.7% | — |
Multilingual Grok 4 Fast leads
Grok 4 Fast: 51.5 (#106), Nemotron 3.5 Lightning: 44.0 (#175)
| Benchmark | Grok 4 Fast | Nemotron 3.5 Lightning |
|---|---|---|
| LMArena Non-English | 1397 | 1292 |
| LMArena Chinese | 1458 | 1356 |
| LMArena French | 1433 | 1369 |
| LMArena German | 1383 | 1280 |
| LMArena Japanese | 1358 | 1213 |
| LMArena Korean | 1359 | 1233 |
| LMArena Russian | 1387 | 1257 |
| LMArena Spanish | 1414 | 1321 |
Instruction Following Grok 4 Fast leads
Grok 4 Fast: 73.4 (#116), Nemotron 3.5 Lightning: 69.8 (#166)
| Benchmark | Grok 4 Fast | Nemotron 3.5 Lightning |
|---|---|---|
| LMArena Instruction Following | 1388 | 1317 |
Long Context Grok 4 Fast leads
Grok 4 Fast: 63.2 (#3), Nemotron 3.5 Lightning: 39.9 (#160)
| Benchmark | Grok 4 Fast | Nemotron 3.5 Lightning |
|---|---|---|
| LMArena Longer Query | 1415 | 1312 |
| Fiction.LiveBench | 94.4% | — |
Writing & Preference Grok 4 Fast leads
Grok 4 Fast: 60.2 (#96), Nemotron 3.5 Lightning: 48.5 (#198)
| Benchmark | Grok 4 Fast | Nemotron 3.5 Lightning |
|---|---|---|
| LMArena Text | 1407 | 1324 |
| LMArena Creative Writing | 1388 | 1254 |
| LMArena Multi-Turn | 1414 | 1327 |
| EQ-Bench Creative Writing | — | 1280 |
Frequently asked questions
Is Grok 4 Fast better than Nemotron 3.5 Lightning?
Grok 4 Fast and Nemotron 3.5 Lightning score almost the same on the Noometry Index (39.0 vs 39.3), so choose on price, context window or the category you care about most.
Is Grok 4 Fast or Nemotron 3.5 Lightning better for coding?
Nemotron 3.5 Lightning scores higher on coding benchmarks: 39.6 versus 32.3 in the Noometry coding category.
How many benchmarks do Grok 4 Fast and Nemotron 3.5 Lightning share?
17 benchmarks have published results for both models. Grok 4 Fast has 30 scored results on Noometry and Nemotron 3.5 Lightning has 18.