# Aion 3.5 vs DeepSeek V4.1 Flash

> DeepSeek V4.1 Flash has enough public results to be ranked (#40); Aion 3.5 does not yet, so treat this comparison as directional.

- Canonical page: https://noometry.com/compare/aion-3-5-vs-deepseek-v4-1-flash
- Last updated: 2026-10-10
- Shared benchmarks: 1

## Summary

- They share 1 benchmark with published results for both. Aion 3.5 scores higher in 1 category and DeepSeek V4.1 Flash in 0 categories; one gap is clear of the uncertainty.
- The widest gap is in writing & preference, where Aion 3.5 leads 74.9 to 65.8.
- DeepSeek V4.1 Flash is cheaper at $0.15 / $0.60 per million input/output tokens, against $3 / $6 for Aion 3.5.
- DeepSeek V4.1 Flash accepts more context: 1M tokens versus 262K.
- DeepSeek V4.1 Flash has downloadable open weights; the other is API-only.

## Snapshot

| | Aion 3.5 | DeepSeek V4.1 Flash |
|---|---|---|
| Provider | AionLabs | DeepSeek |
| Noometry Index | 57.9 | 50.3 |
| Rank | — | 40 |
| Context | 262K | 1M |
| Input $/M | $3 | $0.15 |
| Output $/M | $6 | $0.60 |
| Weights | Proprietary | Open |

## Coding

- Aion 3.5: —
- DeepSeek V4.1 Flash: 52.8 (#29)

| Benchmark | Aion 3.5 | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena WebDev | — | 1620 |
| SciCode | — | 51.9% |
| LMArena Coding | — | 1511 |
| ALE-Bench | — | 1,092 |

## Reasoning

- Aion 3.5: —
- DeepSeek V4.1 Flash: 46.2 (#39)

| Benchmark | Aion 3.5 | DeepSeek V4.1 Flash |
|---|---|---|
| NYT Connections (extended) | — | 89.6% |
| CritPt | — | 14.3% |
| LMArena Hard Prompts | — | 1485 |
| DTBench | — | 89.9% |
| LMCA | — | 47% |
| Surface Evolver Bench | — | 46.3% |
| Epoch Capabilities Index | — | 155.01 |

## Math

- Aion 3.5: —
- DeepSeek V4.1 Flash: 48.4 (#52)

| Benchmark | Aion 3.5 | DeepSeek V4.1 Flash |
|---|---|---|
| ProofBench | — | 54% |
| LMArena Math | — | 1493 |

## Knowledge

- Aion 3.5: —
- DeepSeek V4.1 Flash: 41.6 (#97)

| Benchmark | Aion 3.5 | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena Expert | — | 1505 |

## Multilingual

- Aion 3.5: —
- DeepSeek V4.1 Flash: 55.5 (#29)

| Benchmark | Aion 3.5 | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena Non-English | — | 1452 |
| LMArena Chinese | — | 1506 |
| LMArena French | — | 1448 |
| LMArena Russian | — | 1473 |
| LMArena Spanish | — | 1499 |

## Instruction Following

- Aion 3.5: —
- DeepSeek V4.1 Flash: 77.6 (#24)

| Benchmark | Aion 3.5 | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena Instruction Following | — | 1475 |

## Long Context

- Aion 3.5: —
- DeepSeek V4.1 Flash: 45.2 (#46)

| Benchmark | Aion 3.5 | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena Longer Query | — | 1476 |

## Writing & Preference

- Aion 3.5: 74.9
- DeepSeek V4.1 Flash: 65.8 (#43)

| Benchmark | Aion 3.5 | DeepSeek V4.1 Flash |
|---|---|---|
| EQ-Bench Creative Writing | 1929 | 1540 |
| LMArena Text | — | 1465 |
| LMArena Creative Writing | — | 1436 |
| LMArena Multi-Turn | — | 1460 |

## FAQ

### Is Aion 3.5 better than DeepSeek V4.1 Flash?

DeepSeek V4.1 Flash has enough public results to be ranked (#40); Aion 3.5 does not yet, so treat this comparison as directional.

### Which is cheaper, Aion 3.5 or DeepSeek V4.1 Flash?

DeepSeek V4.1 Flash is cheaper. It lists at $0.15 per million input tokens and $0.60 per million output tokens; Aion 3.5 lists at $3 and $6.

### Which has the bigger context window?

DeepSeek V4.1 Flash does, with 1M tokens against 262K.

### How many benchmarks do Aion 3.5 and DeepSeek V4.1 Flash share?

1 benchmark has published results for both models. Aion 3.5 has 1 scored results on Noometry and DeepSeek V4.1 Flash has 25.