# Aion 3.5 vs Claude Opus 5.5

> Claude Opus 5.5 has enough public results to be ranked (#3); Aion 3.5 does not yet, so treat this comparison as directional.

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

## Summary

- They share 1 benchmark with published results for both. Aion 3.5 scores higher in 0 categories and Claude Opus 5.5 in 1 category; one gap is clear of the uncertainty.
- The widest gap is in writing & preference, where Claude Opus 5.5 leads 78.7 to 74.9.
- Aion 3.5 is cheaper at $3 / $6 per million input/output tokens, against $4 / $20 for Claude Opus 5.5.
- Claude Opus 5.5 accepts more context: 1M tokens versus 262K.

## Snapshot

| | Aion 3.5 | Claude Opus 5.5 |
|---|---|---|
| Provider | AionLabs | Anthropic |
| Noometry Index | 57.9 | 68.5 |
| Rank | — | 3 |
| Context | 262K | 1M |
| Input $/M | $3 | $4 |
| Output $/M | $6 | $20 |
| Weights | Proprietary | Proprietary |

## Coding

- Aion 3.5: —
- Claude Opus 5.5: 71.4 (#1)

| Benchmark | Aion 3.5 | Claude Opus 5.5 |
|---|---|---|
| FrontierCode | — | 54.4% |
| CursorBench | — | 57.8% |
| LMArena WebDev | — | 1820 |
| FrontierSWE | — | 62.3% |
| SciCode | — | 66.9% |
| LMArena Coding | — | 1545 |
| MirrorCode | — | 77.4% |

## Agentic & Tool Use

- Aion 3.5: —
- Claude Opus 5.5: 45.3 (#13)

| Benchmark | Aion 3.5 | Claude Opus 5.5 |
|---|---|---|
| APEX-Agents | — | 73.5% |
| GDP.pdf | — | 30.6% |

## Reasoning

- Aion 3.5: —
- Claude Opus 5.5: 79.5 (#2)

| Benchmark | Aion 3.5 | Claude Opus 5.5 |
|---|---|---|
| ARC-AGI-2 | — | 92.5% |
| NYT Connections (extended) | — | 88.5% |
| ARC-AGI-1 | — | 97.5% |
| CritPt | — | 31.7% |
| EBR-Bench | — | 71.4% |
| LMArena Hard Prompts | — | 1545 |
| Mystery Game Puzzles | — | 71% |
| DTBench | — | 98.9% |
| LMCA | — | 68.2% |

## Math

- Aion 3.5: —
- Claude Opus 5.5: 92.4 (#2)

| Benchmark | Aion 3.5 | Claude Opus 5.5 |
|---|---|---|
| FrontierMath (Tiers 1-3) | — | 91.2% |
| FrontierMath Tier 4 | — | 95% |
| OTIS Mock AIME 2024-2025 | — | 100% |
| ProofBench | — | 100% |

## Knowledge

- Aion 3.5: —
- Claude Opus 5.5: 66.6 (#9)

| Benchmark | Aion 3.5 | Claude Opus 5.5 |
|---|---|---|
| GPQA Diamond | — | 90.6% |
| SimpleQA Verified | — | 72.2% |
| LMArena Expert | — | 1564 |

## Multimodal

- Aion 3.5: —
- Claude Opus 5.5: 56.5 (#2)

| Benchmark | Aion 3.5 | Claude Opus 5.5 |
|---|---|---|
| Furniture Assembly | — | 83.3% |

## Multilingual

- Aion 3.5: —
- Claude Opus 5.5: 59.8 (#1)

| Benchmark | Aion 3.5 | Claude Opus 5.5 |
|---|---|---|
| LMArena Non-English | — | 1513 |
| LMArena Chinese | — | 1572 |
| LMArena Russian | — | 1532 |

## Instruction Following

- Aion 3.5: —
- Claude Opus 5.5: 80.1 (#2)

| Benchmark | Aion 3.5 | Claude Opus 5.5 |
|---|---|---|
| LMArena Instruction Following | — | 1535 |

## Long Context

- Aion 3.5: —
- Claude Opus 5.5: 47.3 (#18)

| Benchmark | Aion 3.5 | Claude Opus 5.5 |
|---|---|---|
| LMArena Longer Query | — | 1540 |

## Writing & Preference

- Aion 3.5: 74.9
- Claude Opus 5.5: 78.7 (#3)

| Benchmark | Aion 3.5 | Claude Opus 5.5 |
|---|---|---|
| EQ-Bench Creative Writing | 1929 | 2050 |
| LMArena Text | — | 1518 |
| LMArena Creative Writing | — | 1538 |
| LMArena Multi-Turn | — | 1520 |

## FAQ

### Is Aion 3.5 better than Claude Opus 5.5?

Claude Opus 5.5 has enough public results to be ranked (#3); Aion 3.5 does not yet, so treat this comparison as directional.

### Which is cheaper, Aion 3.5 or Claude Opus 5.5?

Aion 3.5 is cheaper. It lists at $3 per million input tokens and $6 per million output tokens; Claude Opus 5.5 lists at $4 and $20.

### Which has the bigger context window?

Claude Opus 5.5 does, with 1M tokens against 262K.

### How many benchmarks do Aion 3.5 and Claude Opus 5.5 share?

1 benchmark has published results for both models. Aion 3.5 has 1 scored results on Noometry and Claude Opus 5.5 has 35.