# GPT-5.5 vs Spark-X2.6-4B

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

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

- Shared sourced benchmarks: 7
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

GPT-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

- GPT-5.5 has the higher overall point estimate 69.22 to 40.14. Conditional score ranges do not establish rank confidence.
- The clearest category separation is in coding, where the averages are 62 for GPT-5.5 and 30.6 for Spark-X2.6-4B.
- The biggest single benchmark swing is BrowseComp in Agentic, with scores of 84.4% and 53.1%.
- 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 | GPT-5.5 | Spark-X2.6-4B |
|----------|----------|----------|
| Creator | OpenAI | SparkLLM |
| Type | Proprietary | Open Weight |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 1M |
| Overall Score | 69.22 | 40.14 |
| Benchmarks Covered | 44 | 20 |
| Pricing (input/output) | $5.00 / $30.00 | $0.00 / $0.00 |

## Category Breakdown

### Agentic

- Winner: Directional only
- GPT-5.5 public-lane score: 62.7 (Supported · #23/131)
- Spark-X2.6-4B public-lane score: 33 (Estimated · #89/131)

| Benchmark | GPT-5.5 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 82% | Coming soon | Coming soon |
| CyberGym | 81.8% | Coming soon | Coming soon |
| BrowseComp | 84.4% | 53.1% | GPT-5.5 |
| OSWorld-Verified | 78.7% | Coming soon | Coming soon |
| MCP Atlas | 75.3% | 62.4% | GPT-5.5 |
| Toolathlon | 55.6% | Coming soon | Coming soon |
| τ²-bench results | 98% | 86.9% | GPT-5.5 |
| Gert Labs | 72.93% | Coming soon | Coming soon |
| ResearchClawBench | 17.0% | Coming soon | Coming soon |
| OSWorld 2.0 | 13.0% | Coming soon | Coming soon |
| JobBench | 42.7% | Coming soon | Coming soon |
| ExploitGym | 13.4% | Coming soon | Coming soon |
| Terminal-Bench 2.1 (Vals) | 76.4% | Coming soon | Coming soon |
| ApprenticeBench | 20% | Coming soon | Coming soon |
| MazeBench | 0% | Coming soon | Coming soon |
| BFCL v4 | Coming soon | 71.8% | 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: Directional only
- GPT-5.5 public-lane score: 62 (Supported · #14/152)
- Spark-X2.6-4B public-lane score: 30.6 (Estimated · #95/152)

| Benchmark | GPT-5.5 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Pro | 58.6% | 54.3% | GPT-5.5 |
| Terminal-Bench 2.0 | 82.0% | Coming soon | Coming soon |
| Vibe Code Bench | 69.85% | Coming soon | Coming soon |
| React Native Evals | 84.7% | Coming soon | Coming soon |
| cursorBench31 | 59.2% | Coming soon | Coming soon |
| CursorBench 3.2 | 58.4% | Coming soon | Coming soon |
| FrontierCode 1.1 Main | 43.0% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 85.3% | Coming soon | Coming soon |
| SWE-bench (Vals) | 82.6% | Coming soon | Coming soon |
| PostTrainBench v1.1 | 27.2% | Coming soon | 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: Not comparable
- GPT-5.5 public-lane score: 70.3 (#17/27)
- Spark-X2.6-4B public-lane score: 48.8 (Unranked · 2 rankable rows)

| Benchmark | GPT-5.5 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| MRCR v2 64K-128K | 83.1% | Coming soon | Coming soon |
| MRCR v2 128K-256K | 87.5% | Coming soon | Coming soon |
| ARC-AGI-2 | 85% | Coming soon | Coming soon |
| ARC-AGI-3 | 0.4% | Coming soon | Coming soon |
| ARC-AGI-1 | 95.00% | Coming soon | Coming soon |
| LongBench v2 | Coming soon | 53.3% | Coming soon |

### Multimodal & Grounded

- Winner: Not comparable
- GPT-5.5 public-lane score: 75.5 (#23/55)
- Spark-X2.6-4B public-lane score: Coming soon

| Benchmark | GPT-5.5 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| ExtractBench (LlamaIndex) | 93.57% | Coming soon | Coming soon |
| ParseBench | 67.76% | Coming soon | Coming soon |
| MMMU-Pro | 81.2% | Coming soon | Coming soon |
| MMMU-Pro w/ Python | 83.2% | Coming soon | Coming soon |
| OfficeQA Pro | 54.1% | Coming soon | Coming soon |

### Knowledge

- Winner: Directional only
- GPT-5.5 public-lane score: 72.1 (Supported · #15/187)
- Spark-X2.6-4B public-lane score: 43 (Estimated · #109/187)

| Benchmark | GPT-5.5 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 93.6% | 69.9% | GPT-5.5 |
| GPQA-D | 93.6% | 77.1% | GPT-5.5 |
| HLE | 52.2% | Coming soon | Coming soon |
| HLE w/o tools | 41.4% | 17.9% | GPT-5.5 |
| GPQA Diamond (Vals) | 93.2% | Coming soon | Coming soon |
| MMLU-Pro (Vals) | 88.1% | Coming soon | Coming soon |

### Instruction Following

- Winner: Directional only
- GPT-5.5 public-lane score: 93.3 (#8/149)
- Spark-X2.6-4B public-lane score: 78.2 (#62/149)

| Benchmark | GPT-5.5 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| IFEval | Coming soon | 93.6% | Coming soon |
| IFBench | Coming soon | 75.8% | Coming soon |

### Mathematics

- Winner: Not comparable
- GPT-5.5 public-lane score: 91.2 (Unranked · 3 rankable rows)
- Spark-X2.6-4B public-lane score: 76.4 (Unranked · 3 rankable rows)

| Benchmark | GPT-5.5 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath (legacy) | 51.7% | Coming soon | Coming soon |
| FrontierMath v2 (Tiers 1-3) | 85.263% | Coming soon | Coming soon |
| FrontierMath v2 (Tier 4) | 72.500% | 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, GPT-5.5 or Spark-X2.6-4B?

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

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

The widest category gap is in coding, where the averages are 62 for GPT-5.5 and 30.6 for Spark-X2.6-4B.

### How many benchmarks does GPT-5.5 cover on BenchLM?

GPT-5.5 currently has 44 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

- [GPT-5.5 vs GPT-5.5 Pro](/compare/gpt-5-5-vs-gpt-5-5-pro)
- [Spark-X2.6-4B vs GPT-5.5 Pro](/compare/gpt-5-5-pro-vs-spark-x2-6-4b)
- [GPT-5.5 vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-gpt-5-5)
- [Spark-X2.6-4B vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-spark-x2-6-4b)

## Explore More

- [GPT-5.5 profile](/models/gpt-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)