# Phi-4-reasoning vs Step 3.5 Flash

> Side-by-side benchmark comparison for Phi-4-reasoning and Step 3.5 Flash across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/phi-4-reasoning-vs-step-3-5-flash
- Last updated: October 14, 2026

- Shared sourced benchmarks: 1
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Evidence is too thin for a benchmark verdict: Phi-4-reasoning and Step 3.5 Flash share only 1 sourced benchmark row.

## Summary

- Only 1 shared sourced benchmark row is available. That is not enough for a broad capability verdict, so this mirror does not name an overall winner.
- Step 3.5 Flash has the larger published context window at 256K.

## Model Snapshot

| Property | Phi-4-reasoning | Step 3.5 Flash |
|----------|----------|----------|
| Creator | Microsoft | StepFun |
| Type | Open Weight | Open Weight |
| Reasoning | Reasoning | Non-Reasoning |
| Context | 32K | 256K |
| Independent public score (not head-to-head) | null | 41.96 |
| Benchmarks Covered | 6 | 3 |
| Pricing (input/output) | N/A | $0.10 / $0.30 |

## Category Breakdown

### Coding

- Winner: Insufficient shared evidence
- Phi-4-reasoning public-lane score: Coming soon
- Step 3.5 Flash public-lane score: Coming soon

| Benchmark | Phi-4-reasoning | Step 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| LiveCodeBench | 53.8% | Coming soon | Coming soon |
| SWE-bench Verified | Coming soon | 74.4% | Coming soon |
| LiveCodeBench v6 | Coming soon | 86.4% | Coming soon |

### Knowledge

- Winner: Insufficient shared evidence
- Phi-4-reasoning public-lane score: Coming soon
- Step 3.5 Flash public-lane score: Coming soon

| Benchmark | Phi-4-reasoning | Step 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 65.8% | Coming soon | Coming soon |
| MMLU-Pro | 74.3% | Coming soon | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- Phi-4-reasoning public-lane score: Coming soon
- Step 3.5 Flash public-lane score: Coming soon

| Benchmark | Phi-4-reasoning | Step 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| IFEval | 83.4% | Coming soon | Coming soon |

### Mathematics

- Winner: Insufficient shared evidence
- Phi-4-reasoning public-lane score: Coming soon
- Step 3.5 Flash public-lane score: Coming soon

| Benchmark | Phi-4-reasoning | Step 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| AIME 2024 | 75.3% | Coming soon | Coming soon |
| AIME 2025 | 62.9% | 97.3% | Step 3.5 Flash |

## FAQ

### Is there enough evidence to pick between Phi-4-reasoning and Step 3.5 Flash?

Not yet. The models share only 1 sourced benchmark row, 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

- [Phi-4-reasoning vs Phi-4-reasoning-plus](/compare/phi-4-reasoning-vs-phi-4-reasoning-plus)
- [Step 3.5 Flash vs Phi-4-reasoning-plus](/compare/phi-4-reasoning-plus-vs-step-3-5-flash)
- [Phi-4-reasoning vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-phi-4-reasoning)
- [Step 3.5 Flash vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-step-3-5-flash)

## Explore More

- [Phi-4-reasoning profile](/models/phi-4-reasoning)
- [Step 3.5 Flash profile](/models/step-3-5-flash)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)