# Solar Pro 4 vs Spark-X2.6-4B

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

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

- Shared sourced benchmarks: 5
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Spark-X2.6-4B leads by point estimate. Conditional score ranges do not establish rank confidence. Choose using the category evidence and your own workload tests.

## Summary

- Spark-X2.6-4B has the higher overall point estimate 40.14 to 0. Conditional score ranges do not establish rank confidence.
- The biggest single benchmark swing is GPQA-D in Knowledge, with scores of 89.0% and 77.1%.
- Spark-X2.6-4B is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.
- Spark-X2.6-4B also has the larger context window at 1M.

## Model Snapshot

| Property | Solar Pro 4 | Spark-X2.6-4B |
|----------|----------|----------|
| Creator | Upstage | SparkLLM |
| Type | Proprietary | Open Weight |
| Reasoning | Reasoning | Reasoning |
| Context | 512K | 1M |
| Overall Score | null | 40.14 |
| Benchmarks Covered | 10 | 20 |
| Pricing (input/output) | $0.30 / $1.20 | $0.00 / $0.00 |

## Category Breakdown

### Agentic

- Winner: Not comparable
- Solar Pro 4 public-lane score: Coming soon
- Spark-X2.6-4B public-lane score: 33 (Estimated · #89/131)

| Benchmark | Solar Pro 4 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.1 | 57.0% | Coming soon | Coming soon |
| BrowseComp | 49.2% | 53.1% | Spark-X2.6-4B |
| MCP Atlas | 61.4% | 62.4% | Spark-X2.6-4B |
| APEX-Agents | 18.7% | Coming soon | Coming soon |
| BFCL v4 | Coming soon | 71.8% | Coming soon |
| τ²-bench results | Coming soon | 86.9% | 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: Not comparable
- Solar Pro 4 public-lane score: Coming soon
- Spark-X2.6-4B public-lane score: 30.6 (Estimated · #95/152)

| Benchmark | Solar Pro 4 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.1 | 57.0% | Coming soon | Coming soon |
| SWE-bench Verified | 70.6% | 62.8% | Solar Pro 4 |
| LiveCodeBench | 87.8% | Coming soon | Coming soon |
| SWE-bench Pro | Coming soon | 54.3% | Coming soon |
| SWE Multilingual | Coming soon | 64.7% | Coming soon |
| SciCode | Coming soon | 36.8% | Coming soon |

### Reasoning

- Winner: Not comparable
- Solar Pro 4 public-lane score: Coming soon
- Spark-X2.6-4B public-lane score: 48.8 (Unranked · 2 rankable rows)

| Benchmark | Solar Pro 4 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| LongBench v2 | Coming soon | 53.3% | Coming soon |

### Knowledge

- Winner: Not comparable
- Solar Pro 4 public-lane score: Coming soon
- Spark-X2.6-4B public-lane score: 43 (Estimated · #109/187)

| Benchmark | Solar Pro 4 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| GPQA-D | 89.0% | 77.1% | Solar Pro 4 |
| MMLU-Pro | 86.3% | Coming soon | Coming soon |
| HLE w/o tools | Coming soon | 17.9% | Coming soon |
| GPQA | Coming soon | 69.9% | Coming soon |

### Instruction Following

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

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

### Mathematics

- Winner: Not comparable
- Solar Pro 4 public-lane score: Coming soon
- Spark-X2.6-4B public-lane score: 76.4 (Unranked · 3 rankable rows)

| Benchmark | Solar Pro 4 | Spark-X2.6-4B | Winner |
|-----------|-----------|-----------|--------|
| AIME26 | 95.3% | 91.2% | Solar Pro 4 |
| HMMT Feb 2026 | Coming soon | 81.3% | Coming soon |
| IMOAnswerBench | Coming soon | 75.2% | Coming soon |

## FAQ

### Which is better overall, Solar Pro 4 or Spark-X2.6-4B?

Spark-X2.6-4B has the higher overall point estimate. Conditional score ranges do not establish rank confidence.

### How many benchmarks does Solar Pro 4 cover on BenchLM?

Solar Pro 4 currently has 10 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

- [Solar Pro 4 vs Solar Pro 3](/compare/solar-pro-3-vs-solar-pro-4)
- [Spark-X2.6-4B vs Solar Pro 3](/compare/solar-pro-3-vs-spark-x2-6-4b)
- [Solar Pro 4 vs Solar Pro 2](/compare/solar-pro-2-vs-solar-pro-4)
- [Spark-X2.6-4B vs Solar Pro 2](/compare/solar-pro-2-vs-spark-x2-6-4b)

## Explore More

- [Solar Pro 4 profile](/models/solar-pro-4)
- [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)