# GPT-5.4 nano vs Mistral Medium 3.5 128B

> Side-by-side benchmark comparison for GPT-5.4 nano and Mistral Medium 3.5 128B across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/gpt-5-4-nano-vs-mistral-medium-3-5-128b
- Last updated: September 10, 2026

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

## Quick Verdict

Pick GPT-5.4 nano if you want the stronger benchmark profile. Mistral Medium 3.5 128B only makes more sense when its price, context window, or workload-specific category wins matter more than the overall score.

## Summary

- GPT-5.4 nano leads overall 59.57 to 30.13.
- The clearest category separation is in multimodal & grounded, where the averages are 23.8 for GPT-5.4 nano and 55.6 for Mistral Medium 3.5 128B.
- The biggest single benchmark swing is GPQA Diamond (Vals) in Knowledge, with scores of 77.5% and 34.8%.
- GPT-5.4 nano is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.
- GPT-5.4 nano also has the larger context window at 400K.

## Model Snapshot

| Property | GPT-5.4 nano | Mistral Medium 3.5 128B |
|----------|----------|----------|
| Creator | OpenAI | Mistral |
| Type | Proprietary | Open Weight |
| Reasoning | Reasoning | Reasoning |
| Context | 400K | 256K |
| Overall Score | 59.57 | 30.13 |
| Benchmarks Covered | 18 | 7 |
| Pricing (input/output) | $0.20 / $1.25 | $1.50 / $7.50 |

## Category Breakdown

### Agentic

- Winner: GPT-5.4 nano
- GPT-5.4 nano public-lane score: 34.6 (Supported · #133/152)
- Mistral Medium 3.5 128B public-lane score: 21.9 (Supported · #150/152)

| Benchmark | GPT-5.4 nano | Mistral Medium 3.5 128B | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 46.3% | Coming soon | Coming soon |
| OSWorld-Verified | 39% | Coming soon | Coming soon |
| MCP Atlas | 56.1% | Coming soon | Coming soon |
| Toolathlon | 35.5% | Coming soon | Coming soon |
| τ²-bench results | 92.5% | Coming soon | Coming soon |
| Terminal-Bench 2.1 (Vals) | 41.6% | 39.0% | GPT-5.4 nano |
| τ³-bench results | Coming soon | 91.4% | Coming soon |
| Gert Labs | Coming soon | 39.10% | Coming soon |

### Coding

- Winner: Coming soon
- GPT-5.4 nano public-lane score: 37.1 (Supported · #126/151)
- Mistral Medium 3.5 128B public-lane score: 36.9 (Estimated · #127/151)

| Benchmark | GPT-5.4 nano | Mistral Medium 3.5 128B | Winner |
|-----------|-----------|-----------|--------|
| Vibe Code Bench | 26.10% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 84.0% | Coming soon | Coming soon |
| SWE-bench (Vals) | 69.8% | 66.4% | GPT-5.4 nano |
| SWE-bench Verified | Coming soon | 77.6% | Coming soon |

### Multimodal & Grounded

- Winner: Coming soon
- GPT-5.4 nano public-lane score: 23.8 (#45/48)
- Mistral Medium 3.5 128B public-lane score: 55.6 (Unranked · 1 rankable row)

| Benchmark | GPT-5.4 nano | Mistral Medium 3.5 128B | Winner |
|-----------|-----------|-----------|--------|
| MMMU-Pro | 66.1% | Coming soon | Coming soon |
| MMMU-Pro w/ Python | 69.5% | Coming soon | Coming soon |

### Reasoning

- Winner: Coming soon
- GPT-5.4 nano public-lane score: 73.7 (Unranked · 2 rankable rows)
- Mistral Medium 3.5 128B public-lane score: 68.6 (Unranked · 2 rankable rows)

### Knowledge

- Winner: GPT-5.4 nano
- GPT-5.4 nano public-lane score: 47.4 (Supported · #97/183)
- Mistral Medium 3.5 128B public-lane score: 39 (Supported · #140/183)

| Benchmark | GPT-5.4 nano | Mistral Medium 3.5 128B | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 82.8% | Coming soon | Coming soon |
| HLE | 37.7% | Coming soon | Coming soon |
| HLE w/o tools | 24.3% | Coming soon | Coming soon |
| GPQA Diamond (Vals) | 77.5% | 34.8% | GPT-5.4 nano |
| MMLU-Pro (Vals) | 77.2% | 75.3% | GPT-5.4 nano |

### Instruction Following

- Winner: Coming soon
- GPT-5.4 nano public-lane score: 93.2 (#9/123)
- Mistral Medium 3.5 128B public-lane score: 84 (#48/123)

### Mathematics

- Winner: Coming soon
- GPT-5.4 nano public-lane score: 43.9 (Unranked · 2 rankable rows)
- Mistral Medium 3.5 128B public-lane score: Coming soon

| Benchmark | GPT-5.4 nano | Mistral Medium 3.5 128B | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath v2 (Tiers 1-3) | 25.860% | Coming soon | Coming soon |
| FrontierMath v2 (Tier 4) | 6.250% | Coming soon | Coming soon |

## FAQ

### Which is better overall, GPT-5.4 nano or Mistral Medium 3.5 128B?

GPT-5.4 nano is ahead overall on BenchLM right now.

### Where is the biggest gap between GPT-5.4 nano and Mistral Medium 3.5 128B?

The widest category gap is in multimodal & grounded, where the averages are 23.8 for GPT-5.4 nano and 55.6 for Mistral Medium 3.5 128B.

### How many benchmarks does GPT-5.4 nano cover on BenchLM?

GPT-5.4 nano currently has 18 sourced benchmark scores on BenchLM.

### How many benchmarks does Mistral Medium 3.5 128B cover on BenchLM?

Mistral Medium 3.5 128B currently has 7 sourced benchmark scores on BenchLM.

## Related Comparisons

- [GPT-5.4 nano vs GPT-5.4](/compare/gpt-5-4-vs-gpt-5-4-nano)
- [Mistral Medium 3.5 128B vs GPT-5.4](/compare/gpt-5-4-vs-mistral-medium-3-5-128b)
- [GPT-5.4 nano vs GPT-5.4 mini](/compare/gpt-5-4-mini-vs-gpt-5-4-nano)
- [Mistral Medium 3.5 128B vs GPT-5.4 mini](/compare/gpt-5-4-mini-vs-mistral-medium-3-5-128b)

## Explore More

- [GPT-5.4 nano profile](/models/gpt-5-4-nano)
- [Mistral Medium 3.5 128B profile](/models/mistral-medium-3-5-128b)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)