# Step 5 Preview vs Ternary Bonsai 2 27B

> Side-by-side benchmark comparison for Step 5 Preview and Ternary Bonsai 2 27B across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/step-5-preview-vs-ternary-bonsai-2-27b
- Last updated: September 21, 2026

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

## Quick Verdict

Evidence is too thin for a benchmark verdict: Step 5 Preview and Ternary Bonsai 2 27B 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.
- Ternary Bonsai 2 27B has the lower published output-token price.
- Step 5 Preview has the larger published context window at 1M.

## Model Snapshot

| Property | Step 5 Preview | Ternary Bonsai 2 27B |
|----------|----------|----------|
| Creator | StepFun | Prism ML |
| Type | Pending | Open Weight |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 262K |
| Independent public score (not head-to-head) | null | 50.88 |
| Benchmarks Covered | 22 | 21 |
| Pricing (input/output) | $1.00 / $2.70 | $0.00 / $0.00 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- Step 5 Preview public-lane score: Coming soon
- Ternary Bonsai 2 27B public-lane score: 50.1 (Estimated · #59/154)

| Benchmark | Step 5 Preview | Ternary Bonsai 2 27B | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.1 | 85.0% | 52.8% | Step 5 Preview |
| Terminal-Bench 4.0 | 33.30% | Coming soon | Coming soon |
| CyberGym | 84.7% | Coming soon | Coming soon |
| AutomationBench | 44.0% | Coming soon | Coming soon |
| Toolathlon-Verified | 74.1% | Coming soon | Coming soon |
| MCP Atlas | 85.6% | Coming soon | Coming soon |
| JobBench | 59.0% | Coming soon | Coming soon |
| APEX-Agents | 37.8% | Coming soon | Coming soon |
| DRACO | 83.3% | Coming soon | Coming soon |
| BrowseComp | 88.7% | Coming soon | Coming soon |
| Agents' Last Exam | 29.5% | Coming soon | Coming soon |
| τ²-bench results | Coming soon | 80.2% | Coming soon |
| BFCL v3 | Coming soon | 74.9% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- Step 5 Preview public-lane score: Coming soon
- Ternary Bonsai 2 27B public-lane score: 50.1 (Estimated · #66/156)

| Benchmark | Step 5 Preview | Ternary Bonsai 2 27B | Winner |
|-----------|-----------|-----------|--------|
| DeepSWE | 67.7% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | 85.0% | 52.8% | Step 5 Preview |
| SciCode | 58.9% | Coming soon | Coming soon |
| ProgramBench | 80.5% | Coming soon | Coming soon |
| sweMarathon | 72.7% | Coming soon | Coming soon |
| MLS-Bench Lite | 40.5% | Coming soon | Coming soon |
| LiveCodeBench v6 | Coming soon | 90.1% | Coming soon |
| BigCodeBench | Coming soon | 58.1% | Coming soon |
| SWE-bench Verified | Coming soon | 60.8% | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- Step 5 Preview public-lane score: 78.5 (Unranked · 2 rankable rows)
- Ternary Bonsai 2 27B public-lane score: 73.9 (Unranked · 1 rankable row)

| Benchmark | Step 5 Preview | Ternary Bonsai 2 27B | Winner |
|-----------|-----------|-----------|--------|
| CritPt | 20.9% | Coming soon | Coming soon |

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- Step 5 Preview public-lane score: 61.2 (#28/49)
- Ternary Bonsai 2 27B public-lane score: Coming soon

| Benchmark | Step 5 Preview | Ternary Bonsai 2 27B | Winner |
|-----------|-----------|-----------|--------|
| OfficeQA Pro | 60.3% | Coming soon | Coming soon |
| MMMU-Pro | 76% | Coming soon | Coming soon |
| CharXiv (overall) | Coming soon | 80.0% | Coming soon |
| A-OKVQA | Coming soon | 86.8% | Coming soon |
| OmniDocBench 1.6 | Coming soon | 89.1% | Coming soon |
| RealWorldQA | Coming soon | 80.1% | Coming soon |
| OCRBench V2 | Coming soon | 56.9% | Coming soon |

### Knowledge

- Winner: Insufficient shared evidence
- Step 5 Preview public-lane score: Coming soon
- Ternary Bonsai 2 27B public-lane score: 50.7 (Estimated · #82/186)

| Benchmark | Step 5 Preview | Ternary Bonsai 2 27B | Winner |
|-----------|-----------|-----------|--------|
| GPQA-D | 93.5% | 85.8% | Step 5 Preview |
| HLE | 46.5% | Coming soon | Coming soon |
| MMLU-Redux | Coming soon | 89.1% | Coming soon |
| GPQA | Coming soon | 85.8% | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- Step 5 Preview public-lane score: Coming soon
- Ternary Bonsai 2 27B public-lane score: 71 (#64/124)

| Benchmark | Step 5 Preview | Ternary Bonsai 2 27B | Winner |
|-----------|-----------|-----------|--------|
| IFEval | Coming soon | 91.3% | Coming soon |
| IFBench | Coming soon | 74% | Coming soon |

### Mathematics

- Winner: Insufficient shared evidence
- Step 5 Preview public-lane score: Coming soon
- Ternary Bonsai 2 27B public-lane score: 76.8 (Unranked · 4 rankable rows)

| Benchmark | Step 5 Preview | Ternary Bonsai 2 27B | Winner |
|-----------|-----------|-----------|--------|
| GSM8K | Coming soon | 96.7% | Coming soon |
| MATH-500 | Coming soon | 98.8% | Coming soon |
| AIME 2025 | Coming soon | 95% | Coming soon |
| AIME26 | Coming soon | 95.8% | Coming soon |

## FAQ

### Is there enough evidence to pick between Step 5 Preview and Ternary Bonsai 2 27B?

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

- [Step 5 Preview vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-step-5-preview)
- [Ternary Bonsai 2 27B vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-ternary-bonsai-2-27b)
- [Step 5 Preview vs GPT-6 Astra](/compare/gpt-6-astra-vs-step-5-preview)
- [Ternary Bonsai 2 27B vs GPT-6 Astra](/compare/gpt-6-astra-vs-ternary-bonsai-2-27b)

## Explore More

- [Step 5 Preview profile](/models/step-5-preview)
- [Ternary Bonsai 2 27B profile](/models/ternary-bonsai-2-27b)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)