Model comparison
Aion 3.5 vs Claude Fable 5
Claude Fable 5 has enough public results to be ranked (#5); Aion 3.5 does not yet, so treat this comparison as directional.
Last verified . 1 shared benchmarks.
Summary
- They share 1 benchmark with published results for both. Aion 3.5 scores higher in 0 categories and Claude Fable 5 in 1 category; one gap is clear of the uncertainty.
- Aion 3.5 is cheaper at $3 / $6 per million input/output tokens, against $10 / $50 for Claude Fable 5.
- Claude Fable 5 accepts more context: 1M tokens versus 262K.
Side by side
| Aion 3.5 | Claude Fable 5 | |
|---|---|---|
| Provider | AionLabs | Anthropic |
| Noometry Index | 58.1 | 66.8 |
| Released | — | 2026-06-07 |
| Weights | Proprietary | Proprietary |
| Context window | 262K | 1M |
| Max output | 33K | 128K |
| Input $ / M tokens | $3 | $10 |
| Output $ / M tokens | $6 | $50 |
| Results tracked | 1 | 62 |
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Category by category
Coding Not comparable
Aion 3.5: —, Claude Fable 5: 70.6 (#4)
| Benchmark | Aion 3.5 | Claude Fable 5 |
|---|---|---|
| DeepSWE | — | 69.9% |
| FrontierCode | — | 53.5% |
| LMArena WebDev | — | 1625 |
| FrontierSWE | — | 47% |
| SciCode | — | 61% |
| GSO | — | 78.4% |
| WeirdML | — | 91.9% |
| LMArena Coding | — | 1519 |
| MirrorCode | — | 63.9% |
| ALE-Bench | — | 2,041 |
Agentic & Tool Use Not comparable
Aion 3.5: —, Claude Fable 5: 54.0 (#2)
| Benchmark | Aion 3.5 | Claude Fable 5 |
|---|---|---|
| APEX-Agents | — | 63.6% |
| Remote Labor Index | — | 16.1% |
| τ²-bench Banking | — | 39.7% |
| PostTrainBench | — | 41.8% |
| GBAEval | — | 74.5% |
| GDP.pdf | — | 30% |
| LMArena Search | — | 1230 |
| Vending-Bench 2 | — | 5,680 |
Reasoning Not comparable
Aion 3.5: —, Claude Fable 5: 76.8 (#6)
| Benchmark | Aion 3.5 | Claude Fable 5 |
|---|---|---|
| ARC-AGI-2 | — | 89.2% |
| SimpleBench | — | 81.9% |
| Kagi LLM Benchmark | — | 91.4% |
| NYT Connections (extended) | — | 92.7% |
| ARC-AGI-1 | — | 98.5% |
| CritPt | — | 28.6% |
| Chess Puzzles | — | 41% |
| EnigmaEval | — | 39.3% |
| EBR-Bench | — | 39.5% |
| LMArena Hard Prompts | — | 1508 |
| Mystery Game Puzzles | — | 52% |
| DTBench | — | 98.4% |
| LMCA | — | 61.1% |
| Surface Evolver Bench | — | 95% |
| Bench to the Future 3 | — | 0.13 |
| Epoch Capabilities Index | — | 162.06 |
Math Not comparable
Aion 3.5: —, Claude Fable 5: 88.5 (#5)
| Benchmark | Aion 3.5 | Claude Fable 5 |
|---|---|---|
| FrontierMath (Tiers 1-3) | — | 87% |
| FrontierMath Tier 4 | — | 90.2% |
| OTIS Mock AIME 2024-2025 | — | 100% |
| ProofBench | — | 95% |
| LMArena Math | — | 1519 |
| FrontierMath Erdős | — | 0% |
Knowledge Not comparable
Aion 3.5: —, Claude Fable 5: 62.2 (#25)
| Benchmark | Aion 3.5 | Claude Fable 5 |
|---|---|---|
| GPQA Diamond | — | 85.9% |
| SimpleQA Verified | — | 70.7% |
| LMArena Expert | — | 1534 |
Multimodal Not comparable
Aion 3.5: —, Claude Fable 5: 45.3 (#17)
| Benchmark | Aion 3.5 | Claude Fable 5 |
|---|---|---|
| LMArena Vision | — | 1324 |
| Blueprint-Bench 2 | — | 38.6% |
| Furniture Assembly | — | 35.8% |
| LMArena Document | — | 1496 |
Multilingual Not comparable
Aion 3.5: —, Claude Fable 5: 57.3 (#9)
| Benchmark | Aion 3.5 | Claude Fable 5 |
|---|---|---|
| LMArena Non-English | — | 1481 |
| LMArena Chinese | — | 1543 |
| LMArena French | — | 1505 |
| LMArena German | — | 1486 |
| LMArena Japanese | — | 1506 |
| LMArena Korean | — | 1488 |
| LMArena Russian | — | 1504 |
| LMArena Spanish | — | 1498 |
Instruction Following Not comparable
Aion 3.5: —, Claude Fable 5: 78.6 (#8)
| Benchmark | Aion 3.5 | Claude Fable 5 |
|---|---|---|
| LMArena Instruction Following | — | 1502 |
Long Context Not comparable
Aion 3.5: —, Claude Fable 5: 46.3 (#23)
| Benchmark | Aion 3.5 | Claude Fable 5 |
|---|---|---|
| LMArena Longer Query | — | 1509 |
Writing & Preference Claude Fable 5 leads
Aion 3.5: 74.9, Claude Fable 5: 75.9 (#5)
| Benchmark | Aion 3.5 | Claude Fable 5 |
|---|---|---|
| EQ-Bench Creative Writing | 1929 | 1943 |
| LMArena Text | — | 1491 |
| LMArena Creative Writing | — | 1494 |
| EQ-Bench 4 | — | 1340 |
| LMArena Multi-Turn | — | 1504 |
Frequently asked questions
Is Aion 3.5 better than Claude Fable 5?
Claude Fable 5 has enough public results to be ranked (#5); Aion 3.5 does not yet, so treat this comparison as directional.
Which is cheaper, Aion 3.5 or Claude Fable 5?
Aion 3.5 is cheaper. It lists at $3 per million input tokens and $6 per million output tokens; Claude Fable 5 lists at $10 and $50.
Which has the bigger context window?
Claude Fable 5 does, with 1M tokens against 262K.
How many benchmarks do Aion 3.5 and Claude Fable 5 share?
1 benchmark has published results for both models. Aion 3.5 has 1 scored results on Noometry and Claude Fable 5 has 62.