# Llama 3.1-405B vs Step 3.5 Flash

> Step 3.5 Flash is the stronger model overall, scoring 42.3 to 30.7 on the Noometry Index.

- Canonical page: https://noometry.com/compare/llama-3-1-405b-vs-step-3-5-flash
- Last updated: 2026-10-10
- Shared benchmarks: 17

## Summary

- They share 17 benchmarks with published results for both. Llama 3.1-405B scores higher in 0 categories and Step 3.5 Flash in 8 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in math, where Step 3.5 Flash leads 42.6 to 18.4.

## Snapshot

| | Llama 3.1-405B | Step 3.5 Flash |
|---|---|---|
| Provider | Meta | StepFun |
| Noometry Index | 30.7 | 42.3 |
| Rank | 288 | 116 |
| Context | — | 256K |
| Input $/M | — | $0.10 |
| Output $/M | — | $0.30 |
| Weights | Open | Open |

## Coding

- Llama 3.1-405B: 33.1 (#262)
- Step 3.5 Flash: 42.4 (#105)

| Benchmark | Llama 3.1-405B | Step 3.5 Flash |
|---|---|---|
| LMArena Coding | 1291 | 1436 |
| WeirdML | 21.4% | — |

## Agentic & Tool Use

- Llama 3.1-405B: 21.0 (#140)
- Step 3.5 Flash: —

| Benchmark | Llama 3.1-405B | Step 3.5 Flash |
|---|---|---|
| TheAgentCompany | 7.4% | — |
| Cybench | 7.5% | — |

## Reasoning

- Llama 3.1-405B: 16.8 (#300)
- Step 3.5 Flash: 22.2 (#202)

| Benchmark | Llama 3.1-405B | Step 3.5 Flash |
|---|---|---|
| LMArena Hard Prompts | 1269 | 1411 |
| SimpleBench | 23% | — |
| Kagi LLM Benchmark | 45% | — |
| NYT Connections (extended) | — | 28.4% |
| DTBench | 61.4% | — |
| BIG-Bench Hard | 82.9% | — |
| Epoch Capabilities Index | 128.75 | — |
| ForecastBench | 59.9 | — |
| HellaSwag | 89.2% | — |
| PIQA | 85.9% | — |
| WinoGrande | 89.2% | — |

## Math

- Llama 3.1-405B: 18.4 (#290)
- Step 3.5 Flash: 42.6 (#84)

| Benchmark | Llama 3.1-405B | Step 3.5 Flash |
|---|---|---|
| LMArena Math | 1281 | 1408 |
| MathArena Final-Answer Competitions | — | 66.8% |
| OTIS Mock AIME 2024-2025 | 9.7% | — |
| Omni-MATH | 24.9% | — |
| MATH Level 5 | 49.8% | — |

## Knowledge

- Llama 3.1-405B: 30.4 (#227)
- Step 3.5 Flash: 39.6 (#132)

| Benchmark | Llama 3.1-405B | Step 3.5 Flash |
|---|---|---|
| LMArena Expert | 1243 | 1421 |
| GPQA Diamond | 50.9% | — |
| MMLU-Pro | 72.3% | — |
| Confabulations | 17.6% | — |
| GPQA (HELM) | 52.2% | — |
| ARC (AI2) Challenge | 95.3% | — |
| MMLU | 84.5% | — |
| TriviaQA | 82.7% | — |

## Multilingual

- Llama 3.1-405B: 40.7 (#214)
- Step 3.5 Flash: 50.5 (#119)

| Benchmark | Llama 3.1-405B | Step 3.5 Flash |
|---|---|---|
| LMArena Non-English | 1248 | 1385 |
| LMArena Chinese | 1242 | 1447 |
| LMArena French | 1279 | 1421 |
| LMArena German | 1252 | 1405 |
| LMArena Japanese | 1208 | 1354 |
| LMArena Korean | 1184 | 1352 |
| LMArena Russian | 1265 | 1385 |
| LMArena Spanish | 1260 | 1419 |

## Instruction Following

- Llama 3.1-405B: 65.9 (#214)
- Step 3.5 Flash: 73.1 (#124)

| Benchmark | Llama 3.1-405B | Step 3.5 Flash |
|---|---|---|
| LMArena Instruction Following | 1259 | 1385 |
| IFEval | 81.1% | — |

## Long Context

- Llama 3.1-405B: 38.4 (#197)
- Step 3.5 Flash: 42.8 (#117)

| Benchmark | Llama 3.1-405B | Step 3.5 Flash |
|---|---|---|
| LMArena Longer Query | 1266 | 1402 |

## Writing & Preference

- Llama 3.1-405B: 38.9 (#251)
- Step 3.5 Flash: 58.8 (#113)

| Benchmark | Llama 3.1-405B | Step 3.5 Flash |
|---|---|---|
| LMArena Text | 1284 | 1403 |
| LMArena Creative Writing | 1262 | 1357 |
| LMArena Multi-Turn | 1297 | 1405 |
| EQ-Bench Creative Writing | 870 | — |
| WildBench | 78.3% | — |

## FAQ

### Is Llama 3.1-405B better than Step 3.5 Flash?

Step 3.5 Flash is the stronger model overall, scoring 42.3 to 30.7 on the Noometry Index.

### Is Llama 3.1-405B or Step 3.5 Flash better for coding?

Step 3.5 Flash scores higher on coding benchmarks: 42.4 versus 33.1 in the Noometry coding category.

### How many benchmarks do Llama 3.1-405B and Step 3.5 Flash share?

17 benchmarks have published results for both models. Llama 3.1-405B has 42 scored results on Noometry and Step 3.5 Flash has 19.