# GPT-5.6 Sol vs Spark-X2.6-4B

> Side-by-side benchmark comparison for GPT-5.6 Sol and Spark-X2.6-4B across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

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

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

## Quick Verdict

GPT-5.6 Sol leads by point estimate. Conditional score ranges do not establish rank confidence. Choose using the category evidence and your own workload tests.

## Summary

- GPT-5.6 Sol has the higher overall point estimate 75.32 to 40.14. Conditional score ranges do not establish rank confidence.
- The clearest category separation is in coding, where the averages are 67.4 for GPT-5.6 Sol and 30.6 for Spark-X2.6-4B.
- The biggest single benchmark swing is BrowseComp in Agentic, with scores of 92.2% 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.
- GPT-5.6 Sol also has the larger context window at 1.05M.

## Model Snapshot

| Property | GPT-5.6 Sol | Spark-X2.6-4B |
|----------|----------|----------|
| Creator | OpenAI | SparkLLM |
| Type | Proprietary | Open Weight |
| Reasoning | Reasoning | Reasoning |
| Context | 1.05M | 1M |
| Overall Score | 75.32 | 40.14 |
| Benchmarks Covered | 43 | 20 |
| Pricing (input/output) | $4.00 / $20.00 | $0.00 / $0.00 |

## Category Breakdown

### Agentic

- Winner: Directional only
- GPT-5.6 Sol public-lane score: 68.6 (Supported · #12/131)
- Spark-X2.6-4B public-lane score: 33 (Estimated · #89/131)

| Benchmark | GPT-5.6 Sol | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 3.0 | 34.6% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | 91.9% | Coming soon | Coming soon |
| BrowseComp | 92.2% | 53.1% | GPT-5.6 Sol |
| OSWorld 2.0 | 62.6% | Coming soon | Coming soon |
| CyberGym | 84.5% | Coming soon | Coming soon |
| ExploitGym | 33.7% | Coming soon | Coming soon |
| Toolathlon | 58% | Coming soon | Coming soon |
| Terminal-Bench 2.1 (Vals) | 85.8% | Coming soon | Coming soon |
| ApprenticeBench | 26% | 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 |
| 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-5.6 Sol public-lane score: 67.4 (Supported · #11/152)
- Spark-X2.6-4B public-lane score: 30.6 (Estimated · #95/152)

| Benchmark | GPT-5.6 Sol | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| Bug Hunt Bench | 42.0 fixes | Coming soon | Coming soon |
| SWE-bench Pro | 64.6% | 54.3% | GPT-5.6 Sol |
| Terminal-Bench 2.1 | 91.9% | Coming soon | Coming soon |
| DeepSWE | 72.7% | Coming soon | Coming soon |
| FrontierCode 1.1 Extended | 60.6% | Coming soon | Coming soon |
| FrontierSWE v2 | 32.2% | Coming soon | Coming soon |
| CursorBench 3.2 | 67.2% | Coming soon | Coming soon |
| VulcanBench v3 | 87.0% | Coming soon | Coming soon |
| VulcanBench CII v1 | 86.5% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 82.6% | Coming soon | Coming soon |
| SWE-bench (Vals) | 96.2% | Coming soon | Coming soon |
| CursorBench 4.0 | 41.7% | Coming soon | Coming soon |
| PostTrainBench v1.1 | 36.2% | 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-5.6 Sol public-lane score: 76.4 (#13/27)
- Spark-X2.6-4B public-lane score: 48.8 (Unranked · 2 rankable rows)

| Benchmark | GPT-5.6 Sol | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| ARC-AGI-2 | 92.5% | Coming soon | Coming soon |
| ARC-AGI-3 | 7.8% | Coming soon | Coming soon |
| GeneBench-Pro | 28.7% | Coming soon | Coming soon |
| ARC-AGI-1 | 96.50% | Coming soon | Coming soon |
| LongBench v2 | Coming soon | 53.3% | Coming soon |

### Multimodal & Grounded

- Winner: Not comparable
- GPT-5.6 Sol public-lane score: 89.8 (#6/55)
- Spark-X2.6-4B public-lane score: Coming soon

| Benchmark | GPT-5.6 Sol | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| ExtractBench (LlamaIndex) | 93.77% | Coming soon | Coming soon |
| ParseBench | 75.35% | Coming soon | Coming soon |
| MMMU-Pro | 83% | Coming soon | Coming soon |
| MMMU-Pro w/ Python | 84.6% | Coming soon | Coming soon |

### Knowledge

- Winner: Directional only
- GPT-5.6 Sol public-lane score: 77.3 (Supported · #11/187)
- Spark-X2.6-4B public-lane score: 43 (Estimated · #109/187)

| Benchmark | GPT-5.6 Sol | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 94.6% | 69.9% | GPT-5.6 Sol |
| GPQA-D | 94.6% | 77.1% | GPT-5.6 Sol |
| HLE-Verified | 54.5% | Coming soon | Coming soon |
| LABBench2 | 82.1% | Coming soon | Coming soon |
| HealthBench Professional | 60.5% | Coming soon | Coming soon |
| HealthBench Hard | 33.1% | Coming soon | Coming soon |
| GPQA Diamond (Vals) | 95.2% | Coming soon | Coming soon |
| MMLU-Pro (Vals) | 89.1% | Coming soon | Coming soon |
| HLE w/o tools | Coming soon | 17.9% | Coming soon |

### Instruction Following

- Winner: Directional only
- GPT-5.6 Sol public-lane score: 89.1 (#31/149)
- Spark-X2.6-4B public-lane score: 78.2 (#62/149)

| Benchmark | GPT-5.6 Sol | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| Gray Swan IPI (15 attempts) | 27.0% | Coming soon | Coming soon |
| IFEval | Coming soon | 93.6% | Coming soon |
| IFBench | Coming soon | 75.8% | Coming soon |

### Mathematics

- Winner: Not comparable
- GPT-5.6 Sol public-lane score: 95.8 (Unranked · 3 rankable rows)
- Spark-X2.6-4B public-lane score: 76.4 (Unranked · 3 rankable rows)

| Benchmark | GPT-5.6 Sol | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath (legacy) | 89% | Coming soon | Coming soon |
| FrontierMath v2 (Tiers 1-3) | 89.000% | Coming soon | Coming soon |
| FrontierMath v2 (Tier 4) | 83.000% | 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, GPT-5.6 Sol or Spark-X2.6-4B?

GPT-5.6 Sol has the higher overall point estimate. Conditional score ranges do not establish rank confidence.

### Where is the biggest gap between GPT-5.6 Sol and Spark-X2.6-4B?

The widest category gap is in coding, where the averages are 67.4 for GPT-5.6 Sol and 30.6 for Spark-X2.6-4B.

### How many benchmarks does GPT-5.6 Sol cover on BenchLM?

GPT-5.6 Sol currently has 43 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-5.6 Sol vs GPT-5.6 Terra](/compare/gpt-5-6-sol-vs-gpt-5-6-terra)
- [Spark-X2.6-4B vs GPT-5.6 Terra](/compare/gpt-5-6-terra-vs-spark-x2-6-4b)
- [GPT-5.6 Sol vs GPT-5.6 Luna](/compare/gpt-5-6-luna-vs-gpt-5-6-sol)
- [Spark-X2.6-4B vs GPT-5.6 Luna](/compare/gpt-5-6-luna-vs-spark-x2-6-4b)

## Explore More

- [GPT-5.6 Sol profile](/models/gpt-5-6-sol)
- [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)