# Hy4 preview vs Seed 2.1 Pro

> Side-by-side benchmark comparison for Hy4 preview and Seed 2.1 Pro across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/hy4-preview-vs-seed-2-1-pro
- Last updated: September 10, 2026

- Shared sourced benchmarks: 3
- HTML indexing: indexable
- Ranking lane: BenchAlign v5

## Quick Verdict

Evidence is too thin for a benchmark verdict: Hy4 preview and Seed 2.1 Pro share only 3 sourced benchmark rows.

## Summary

- Only 3 shared sourced benchmark rows are available. That is not enough for a broad capability verdict, so this mirror does not name an overall winner.
- Seed 2.1 Pro has the lower published output-token price.
- Hy4 preview has the larger published context window at 1M.

## Model Snapshot

| Property | Hy4 preview | Seed 2.1 Pro |
|----------|----------|----------|
| Creator | Tencent | ByteDance |
| Type | Open Weight | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 256K |
| Independent public score (not head-to-head) | 61.08 | null |
| Benchmarks Covered | 28 | 11 |
| Pricing (input/output) | $0.00 / $0.00 | Pricing unavailable / Pricing unavailable |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- Hy4 preview public-lane score: 58.2 (Estimated · #30/152)
- Seed 2.1 Pro public-lane score: Coming soon

| Benchmark | Hy4 preview | Seed 2.1 Pro | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.1 | 85.4% | 71.0% | Hy4 preview |
| CyberGym | 78.4% | Coming soon | Coming soon |
| WideResearch | 83.9% | Coming soon | Coming soon |
| DRACO | 77.2% | Coming soon | Coming soon |
| MCP Atlas | 83.7% | Coming soon | Coming soon |
| Toolathlon-Verified | 74.1% | Coming soon | Coming soon |
| APEX-Agents | 37.1% | Coming soon | Coming soon |
| skillsBench | 62.9% | Coming soon | Coming soon |
| JobBench | 61.7% | Coming soon | Coming soon |
| Agents' Last Exam | 22.8% | Coming soon | Coming soon |
| AutomationBench | 32.1% | Coming soon | Coming soon |
| BankerToolBench | 78.6% | Coming soon | Coming soon |
| HLE w/ tools | 55.4% | Coming soon | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- Hy4 preview public-lane score: 59.2 (Estimated · #24/151)
- Seed 2.1 Pro public-lane score: Coming soon

| Benchmark | Hy4 preview | Seed 2.1 Pro | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.1 | 85.4% | 71.0% | Hy4 preview |
| SWE-bench Pro | 65.7% | Coming soon | Coming soon |
| SWE Multilingual | 82.9% | Coming soon | Coming soon |
| DeepSWE | 64.3% | Coming soon | Coming soon |
| NL2Repo | 58.9% | 47% | Hy4 preview |
| ProgramBench | 17.5% | Coming soon | Coming soon |
| PostTrain Bench | 35.6% | Coming soon | Coming soon |
| sweMarathon | 31.9% | Coming soon | Coming soon |

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- Hy4 preview public-lane score: 84.8 (Unranked · 1 rankable row)
- Seed 2.1 Pro public-lane score: Coming soon

| Benchmark | Hy4 preview | Seed 2.1 Pro | Winner |
|-----------|-----------|-----------|--------|
| OfficeQA Pro | 66.2% | Coming soon | Coming soon |
| MathVision | Coming soon | 92.6% | Coming soon |
| MMMU-Pro | Coming soon | 81.6% | Coming soon |
| ZeroBench | Coming soon | 18.0% | Coming soon |
| BabyVision | Coming soon | 73.7% | Coming soon |
| CharXiv | Coming soon | 85.4% | Coming soon |
| ERQA | Coming soon | 72.0% | Coming soon |
| Video-MME | Coming soon | 89.2% | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- Hy4 preview public-lane score: Coming soon
- Seed 2.1 Pro public-lane score: Coming soon

| Benchmark | Hy4 preview | Seed 2.1 Pro | Winner |
|-----------|-----------|-----------|--------|
| CritPt | 16.9% | Coming soon | Coming soon |

### Knowledge

- Winner: Insufficient shared evidence
- Hy4 preview public-lane score: 56.5 (Estimated · #47/183)
- Seed 2.1 Pro public-lane score: Coming soon

| Benchmark | Hy4 preview | Seed 2.1 Pro | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 92.3% | Coming soon | Coming soon |
| GPQA-D | 92.3% | Coming soon | Coming soon |
| HLE | 55.4% | Coming soon | Coming soon |
| HLE w/o tools | 43.4% | Coming soon | Coming soon |
| SuperGPQA | Coming soon | 70.8% | Coming soon |

### Mathematics

- Winner: Insufficient shared evidence
- Hy4 preview public-lane score: Coming soon
- Seed 2.1 Pro public-lane score: Coming soon

| Benchmark | Hy4 preview | Seed 2.1 Pro | Winner |
|-----------|-----------|-----------|--------|
| Apex | 74.2% | Coming soon | Coming soon |

## FAQ

### Is there enough evidence to pick between Hy4 preview and Seed 2.1 Pro?

Not yet. The models share only 3 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

- [Hy4 preview vs Seed 2.1 Turbo](/compare/hy4-preview-vs-seed-2-1-turbo)
- [Seed 2.1 Pro vs Seed 2.1 Turbo](/compare/seed-2-1-pro-vs-seed-2-1-turbo)
- [Hy4 preview vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-hy4-preview)
- [Seed 2.1 Pro vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-seed-2-1-pro)

## Explore More

- [Hy4 preview profile](/models/hy4-preview)
- [Seed 2.1 Pro profile](/models/seed-2-1-pro)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)