# Nemotron 3.5 Bolt E4B BF16 vs Spark-X2.6-4B

> Side-by-side benchmark comparison for Nemotron 3.5 Bolt E4B BF16 and Spark-X2.6-4B across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/nemotron-3-5-bolt-e4b-bf16-vs-spark-x2-6-4b
- Last updated: October 23, 2026

- Shared sourced benchmarks: 2
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Evidence is too thin for a benchmark verdict: Nemotron 3.5 Bolt E4B BF16 and Spark-X2.6-4B share only 2 sourced benchmark rows.

## Summary

- Only 2 shared sourced benchmark rows are available. That is not enough for a broad capability verdict, so this mirror does not name an overall winner.
- Spark-X2.6-4B has the lower published output-token price.
- Spark-X2.6-4B has the larger published context window at 1M.

## Model Snapshot

| Property | Nemotron 3.5 Bolt E4B BF16 | Spark-X2.6-4B |
|----------|----------|----------|
| Creator | NVIDIA | SparkLLM |
| Type | Open Weight | Open Weight |
| Reasoning | Reasoning | Reasoning |
| Context | 64K | 1M |
| Independent public score (not head-to-head) | null | 39.69 |
| Benchmarks Covered | 19 | 20 |
| Pricing (input/output) | Pricing unavailable / Pricing unavailable | $0.00 / $0.00 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- Nemotron 3.5 Bolt E4B BF16 public-lane score: Coming soon
- Spark-X2.6-4B public-lane score: 32.6 (Estimated · #91/132)

| Benchmark | Nemotron 3.5 Bolt E4B BF16 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| BFCL v3 | 68.5% | Coming soon | Coming soon |
| When2Call Multi-Turn | 63.36% | Coming soon | Coming soon |
| ToolSandbox | 68.77% | Coming soon | Coming soon |
| τ²-bench results | 55.1% | 86.9% | Spark-X2.6-4B |
| RelyToolBench | 63.16% | Coming soon | Coming soon |
| BFCL v4 | Coming soon | 71.8% | Coming soon |
| MCP Atlas | Coming soon | 62.4% | Coming soon |
| BrowseComp | Coming soon | 53.1% | Coming soon |
| HLE w/ tools | Coming soon | 36.9% | Coming soon |
| τ³-bench results | Coming soon | 34.7% | Coming soon |
| Claw-Eval | Coming soon | 69.9% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- Nemotron 3.5 Bolt E4B BF16 public-lane score: Coming soon
- Spark-X2.6-4B public-lane score: 30.3 (Estimated · #99/153)

| Benchmark | Nemotron 3.5 Bolt E4B BF16 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Pro | Coming soon | 54.3% | Coming soon |
| SWE-bench Verified | Coming soon | 62.8% | Coming soon |
| SWE Multilingual | Coming soon | 64.7% | Coming soon |
| SciCode | Coming soon | 36.8% | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- Nemotron 3.5 Bolt E4B BF16 public-lane score: 29 (Unranked · 1 rankable row)
- Spark-X2.6-4B public-lane score: 48.8 (Unranked · 2 rankable rows)

| Benchmark | Nemotron 3.5 Bolt E4B BF16 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| RULER (64K) | 86.99% | Coming soon | Coming soon |
| LongMemEval | 72.10% | Coming soon | Coming soon |
| LongBench v2 | 50.5% | 53.3% | Spark-X2.6-4B |

### Knowledge

- Winner: Insufficient shared evidence
- Nemotron 3.5 Bolt E4B BF16 public-lane score: Coming soon
- Spark-X2.6-4B public-lane score: 42.1 (Estimated · #111/187)

| Benchmark | Nemotron 3.5 Bolt E4B BF16 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| GaRAGe | 42.61% | Coming soon | Coming soon |
| RAGTruth (provider reports) | 77.59% | Coming soon | Coming soon |
| GPQA-D | Coming soon | 77.1% | Coming soon |
| HLE w/o tools | Coming soon | 17.9% | Coming soon |
| GPQA | Coming soon | 69.9% | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- Nemotron 3.5 Bolt E4B BF16 public-lane score: Coming soon
- Spark-X2.6-4B public-lane score: 78.2 (#64/153)

| Benchmark | Nemotron 3.5 Bolt E4B BF16 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| MultiChallenge (provider reports) | 53.10% | Coming soon | Coming soon |
| Brevity Benchmark | 82.52% | Coming soon | Coming soon |
| RoleBench | 67.05% | Coming soon | Coming soon |
| RoleMRC | 80.63% | Coming soon | Coming soon |
| IHEval | 84.79% | Coming soon | Coming soon |
| AgentIF | 25.81% | Coming soon | Coming soon |
| InverseIFEval | 46.84% | Coming soon | Coming soon |
| StructEval-T | 80.40% | Coming soon | Coming soon |
| SysBench | 67.88% | Coming soon | Coming soon |
| IFEval | Coming soon | 93.6% | Coming soon |
| IFBench | Coming soon | 75.8% | Coming soon |

### Mathematics

- Winner: Insufficient shared evidence
- Nemotron 3.5 Bolt E4B BF16 public-lane score: Coming soon
- Spark-X2.6-4B public-lane score: 76.4 (Unranked · 3 rankable rows)

| Benchmark | Nemotron 3.5 Bolt E4B BF16 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| AIME26 | Coming soon | 91.2% | Coming soon |
| HMMT Feb 2026 | Coming soon | 81.3% | Coming soon |
| IMOAnswerBench | Coming soon | 75.2% | Coming soon |

## FAQ

### Is there enough evidence to pick between Nemotron 3.5 Bolt E4B BF16 and Spark-X2.6-4B?

Not yet. The models share only 2 sourced benchmark rows, so this mirror reports the available measurements and metadata without naming a broad winner.

### What can I compare safely on this page?

Published pricing, context windows, model type, and individual shared benchmark rows are directly comparable. Independent overall scores and non-overlapping benchmark coverage are labeled separately and should not be read as a controlled head-to-head result.

## Related Comparisons

- [Nemotron 3.5 Bolt E4B BF16 vs Nemotron 3.5 Bolt E4B](/compare/nemotron-3-5-bolt-e4b-vs-nemotron-3-5-bolt-e4b-bf16)
- [Spark-X2.6-4B vs Nemotron 3.5 Bolt E4B](/compare/nemotron-3-5-bolt-e4b-vs-spark-x2-6-4b)
- [Nemotron 3.5 Bolt E4B BF16 vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-nemotron-3-5-bolt-e4b-bf16)
- [Spark-X2.6-4B vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-spark-x2-6-4b)

## Explore More

- [Nemotron 3.5 Bolt E4B BF16 profile](/models/nemotron-3-5-bolt-e4b-bf16)
- [Spark-X2.6-4B profile](/models/spark-x2-6-4b)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)