# Claude Opus 5.5 vs Spark-X2.6-4B

> Side-by-side benchmark comparison for Claude Opus 5.5 and Spark-X2.6-4B across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/claude-opus-5-5-vs-spark-x2-6-4b
- Last updated: October 20, 2026

- Shared sourced benchmarks: 4
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Claude Opus 5.5 leads by point estimate. Conditional score ranges do not establish rank confidence. Choose using the category evidence and your own workload tests.

## Summary

- Claude Opus 5.5 has the higher overall point estimate 86.69 to 40.14. Conditional score ranges do not establish rank confidence.
- The clearest category separation is in agentic, where the averages are 90.4 for Claude Opus 5.5 and 33 for Spark-X2.6-4B.
- The biggest single benchmark swing is HLE w/o tools in Knowledge, with scores of 64.4% and 17.9%.
- Spark-X2.6-4B is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.

## Model Snapshot

| Property | Claude Opus 5.5 | Spark-X2.6-4B |
|----------|----------|----------|
| Creator | Anthropic | SparkLLM |
| Type | Proprietary | Open Weight |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 1M |
| Overall Score | 86.69 | 40.14 |
| Benchmarks Covered | 63 | 20 |
| Pricing (input/output) | $4.00 / $20.00 | $0.00 / $0.00 |

## Category Breakdown

### Agentic

- Winner: Directional only
- Claude Opus 5.5 public-lane score: 90.4 (Supported · #1/131)
- Spark-X2.6-4B public-lane score: 33 (Estimated · #89/131)

| Benchmark | Claude Opus 5.5 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 4.0 | 66.40% | Coming soon | Coming soon |
| Terminal-Bench-Science 0.1 | 58.7% | Coming soon | Coming soon |
| AutomationBench | 40.0% | Coming soon | Coming soon |
| HLE w/ tools | 67.7% | 36.9% | Claude Opus 5.5 |
| OSWorld 2.0 | 48.7% | Coming soon | Coming soon |
| LAB all-pass (Harvey held-out) | 8.3% | Coming soon | Coming soon |
| LAB criterion-pass (Harvey held-out) | 91.2% | Coming soon | Coming soon |
| Toolathlon-Verified | 77.8% | Coming soon | Coming soon |
| Toolathlon Verified Pass@3 | 82.4% | Coming soon | Coming soon |
| Toolathlon Verified Pass³ | 72.2% | Coming soon | Coming soon |
| Toolathlon Verified avg. turns | 26.9 turns | Coming soon | Coming soon |
| CWE-bench v1 | 67.0% | Coming soon | Coming soon |
| Hermes Index | 63.3% | Coming soon | Coming soon |
| Hermes Bench | 76.7% | Coming soon | Coming soon |
| MazeBench | 13% | Coming soon | Coming soon |
| BFCL v4 | Coming soon | 71.8% | Coming soon |
| τ²-bench results | Coming soon | 86.9% | Coming soon |
| MCP Atlas | Coming soon | 62.4% | Coming soon |
| BrowseComp | Coming soon | 53.1% | Coming soon |
| τ³-bench results | Coming soon | 34.7% | Coming soon |
| Claw-Eval | Coming soon | 69.9% | Coming soon |

### Coding

- Winner: Directional only
- Claude Opus 5.5 public-lane score: 82.7 (Supported · #2/152)
- Spark-X2.6-4B public-lane score: 30.6 (Estimated · #95/152)

| Benchmark | Claude Opus 5.5 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| FrontierCode 1.1 Main | 54.4% | Coming soon | Coming soon |
| CursorBench 4.0 | 57.8% | Coming soon | Coming soon |
| SWE-bench Pro | 89.9% | 54.3% | Claude Opus 5.5 |
| SWE Multilingual | 93.9% | 64.7% | Claude Opus 5.5 |
| SWE Multimodal | 61.4% | Coming soon | Coming soon |
| DeepSWE | 74.2% | Coming soon | Coming soon |
| FrontierCode 1.1 Extended | 63.6% | Coming soon | Coming soon |
| FrontierSWE v2 | 62.3% | Coming soon | Coming soon |
| ProgramBench | 91.2% | Coming soon | Coming soon |
| PostTrainBench v1.1 | 49.3% | Coming soon | Coming soon |
| Bug Hunt Bench | 41.7 fixes | Coming soon | Coming soon |
| SWE-bench Verified | Coming soon | 62.8% | Coming soon |
| SciCode | Coming soon | 36.8% | Coming soon |

### Reasoning

- Winner: Not comparable
- Claude Opus 5.5 public-lane score: 86.1 (#4/27)
- Spark-X2.6-4B public-lane score: 48.8 (Unranked · 2 rankable rows)

| Benchmark | Claude Opus 5.5 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| STEMBench | 2.62 | Coming soon | Coming soon |
| ARC-AGI-1 | 97.50% | Coming soon | Coming soon |
| ARC-AGI-2 | 91.7% | Coming soon | Coming soon |
| GraphWalks BFS 256K–1M | 66.8% | Coming soon | Coming soon |
| LongBench v2 | Coming soon | 53.3% | Coming soon |

### Multimodal & Grounded

- Winner: Not comparable
- Claude Opus 5.5 public-lane score: 92.2 (#3/55)
- Spark-X2.6-4B public-lane score: Coming soon

| Benchmark | Claude Opus 5.5 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| ExtractBench Pro | 51% | Coming soon | Coming soon |
| ExtractBench (LlamaIndex) | 86.06% | Coming soon | Coming soon |
| ParseBench | 79.85% | Coming soon | Coming soon |
| Chartography (tools) | 89.0% | Coming soon | Coming soon |
| Chartography (no tools) | 64.4% | Coming soon | Coming soon |
| BenchCAD Vision2Code (no tools) | 0.730 | Coming soon | Coming soon |
| BenchCAD Vision2Code (tools) | 0.962 | Coming soon | Coming soon |
| Biomedical image analysis | 71.4% | Coming soon | Coming soon |
| OfficeQA | 78.9% | Coming soon | Coming soon |
| OfficeQA Pro | 67.7% | Coming soon | Coming soon |

### Knowledge

- Winner: Directional only
- Claude Opus 5.5 public-lane score: 90.3 (Supported · #1/187)
- Spark-X2.6-4B public-lane score: 43 (Estimated · #109/187)

| Benchmark | Claude Opus 5.5 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| HLE w/o tools | 64.4% | 17.9% | Claude Opus 5.5 |
| HealthBench (raw) | 68.1% | Coming soon | Coming soon |
| HealthBench (length-adjusted) | 60.6% | Coming soon | Coming soon |
| HealthBench Professional | 65.6% | Coming soon | Coming soon |
| HealthBench Professional (raw) | 77.1% | Coming soon | Coming soon |
| BioMysteryBench (human-solvable) | 89.3% | Coming soon | Coming soon |
| BioMysteryBench (human-difficult) | 50.0% | Coming soon | Coming soon |
| SpatialBench Verified | 72.0% | Coming soon | Coming soon |
| SingleCellBench | 61.2% | Coming soon | Coming soon |
| Morphology-to-molecule matching | 34.0% | Coming soon | Coming soon |
| Medicinal chemistry | 63.5% | Coming soon | Coming soon |
| Protein Design | 60.2% | Coming soon | Coming soon |
| Protein Design library ranking | 56.0% | Coming soon | Coming soon |
| De novo protein-binder design | 82.6% | Coming soon | Coming soon |
| Protocols (troubleshooting) | 73.7% | Coming soon | Coming soon |
| Protocols (understanding) | 69.0% | Coming soon | Coming soon |
| GPQA-D | Coming soon | 77.1% | Coming soon |
| GPQA | Coming soon | 69.9% | Coming soon |

### Multilingual

- Winner: Not comparable
- Claude Opus 5.5 public-lane score: Coming soon
- Spark-X2.6-4B public-lane score: Coming soon

| Benchmark | Claude Opus 5.5 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| GMMLU | 94.3% | Coming soon | Coming soon |
| MILU | 93.1% | Coming soon | Coming soon |

### Instruction Following

- Winner: Not comparable
- Claude Opus 5.5 public-lane score: Coming soon
- Spark-X2.6-4B public-lane score: 78.2 (#62/149)

| Benchmark | Claude Opus 5.5 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| Gray Swan IPI (15 attempts) | 1.0% | Coming soon | Coming soon |
| IFEval | Coming soon | 93.6% | Coming soon |
| IFBench | Coming soon | 75.8% | Coming soon |

### Mathematics

- Winner: Not comparable
- Claude Opus 5.5 public-lane score: 97.3 (Unranked · 4 rankable rows)
- Spark-X2.6-4B public-lane score: 76.4 (Unranked · 3 rankable rows)

| Benchmark | Claude Opus 5.5 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| ArXivMath Aug. 2026 (no tools) | 91.2% | Coming soon | Coming soon |
| ArXivMath Aug. 2026 (tools) | 96.9% | Coming soon | Coming soon |
| FrontierMath v2 (Tiers 1-3) | 91.228% | Coming soon | Coming soon |
| FrontierMath v2 (Tier 4) | 95.000% | Coming soon | Coming soon |
| AIME26 | Coming soon | 91.2% | Coming soon |
| HMMT Feb 2026 | Coming soon | 81.3% | Coming soon |
| IMOAnswerBench | Coming soon | 75.2% | Coming soon |

## FAQ

### Which is better overall, Claude Opus 5.5 or Spark-X2.6-4B?

Claude Opus 5.5 has the higher overall point estimate. Conditional score ranges do not establish rank confidence.

### Where is the biggest gap between Claude Opus 5.5 and Spark-X2.6-4B?

The widest category gap is in agentic, where the averages are 90.4 for Claude Opus 5.5 and 33 for Spark-X2.6-4B.

### How many benchmarks does Claude Opus 5.5 cover on BenchLM?

Claude Opus 5.5 currently has 63 sourced benchmark scores on BenchLM.

### How many benchmarks does Spark-X2.6-4B cover on BenchLM?

Spark-X2.6-4B currently has 20 sourced benchmark scores on BenchLM.

## Related Comparisons

- [Claude Opus 5.5 vs GPT-6.1 Sol](/compare/claude-opus-5-5-vs-gpt-6-1-sol)
- [Spark-X2.6-4B vs GPT-6.1 Sol](/compare/gpt-6-1-sol-vs-spark-x2-6-4b)
- [Claude Opus 5.5 vs GPT-6 Astra](/compare/claude-opus-5-5-vs-gpt-6-astra)
- [Spark-X2.6-4B vs GPT-6 Astra](/compare/gpt-6-astra-vs-spark-x2-6-4b)

## Explore More

- [Claude Opus 5.5 profile](/models/claude-opus-5-5)
- [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)