Model comparison
Aion 3.5 vs GPT-5.1
GPT-5.1 has enough public results to be ranked (#53); Aion 3.5 does not yet, so treat this comparison as directional.
Last verified . 0 shared benchmarks.
Summary
- The widest gap is in writing & preference, where Aion 3.5 leads 74.9 to 64.5.
- GPT-5.1 is cheaper at $1.25 / $10 per million input/output tokens, against $3 / $6 for Aion 3.5.
- GPT-5.1 accepts more context: 400K tokens versus 262K.
Side by side
| Aion 3.5 | GPT-5.1 | |
|---|---|---|
| Provider | AionLabs | OpenAI |
| Noometry Index | 58.1 | 49.0 |
| Released | — | 2025-11-13 |
| Weights | Proprietary | Proprietary |
| Context window | 262K | 400K |
| Max output | 33K | 128K |
| Input $ / M tokens | $3 | $1.25 |
| Output $ / M tokens | $6 | $10 |
| Results tracked | 1 | 63 |
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Category by category
Coding Not comparable
Aion 3.5: —, GPT-5.1: 46.4 (#66)
| Benchmark | Aion 3.5 | GPT-5.1 |
|---|---|---|
| SWE-bench Verified | — | 68% |
| SWE-bench Verified (bash only) | — | 66% |
| LMArena WebDev | — | 1395 |
| SciCode | — | 43.3% |
| GSO | — | 13.7% |
| WeirdML | — | 60.8% |
| LiveBench Coding | — | 72.5% |
| LMArena Coding | — | 1454 |
| ALE-Bench | — | 1,192 |
Agentic & Tool Use Not comparable
Aion 3.5: —, GPT-5.1: 32.7 (#60)
| Benchmark | Aion 3.5 | GPT-5.1 |
|---|---|---|
| Terminal-Bench | — | 47.6% |
| DeepResearch Bench | — | 42.8% |
| LMArena Search | — | 1199 |
| Vending-Bench 2 | — | 1,473 |
Reasoning Not comparable
Aion 3.5: —, GPT-5.1: 39.8 (#58)
| Benchmark | Aion 3.5 | GPT-5.1 |
|---|---|---|
| ARC-AGI-2 | — | 17.6% |
| SimpleBench | — | 53.2% |
| ARC-AGI-1 | — | 72.8% |
| CritPt | — | 4.9% |
| Chess Puzzles | — | 32% |
| EnigmaEval | — | 11.2% |
| LiveBench Reasoning | — | 95.8% |
| LMArena Hard Prompts | — | 1457 |
| Mystery Game Puzzles | — | 19% |
| DTBench | — | 90.1% |
| LiveBench Data Analysis | — | 72.1% |
| LMCA | — | 43.9% |
| Epoch Capabilities Index | — | 149.64 |
| ForecastBench | — | 58.1 |
| LiveBench | — | 78.8% |
Math Not comparable
Aion 3.5: —, GPT-5.1: 52.2 (#51)
| Benchmark | Aion 3.5 | GPT-5.1 |
|---|---|---|
| OTIS Mock AIME 2024-2025 | — | 88.6% |
| Omni-MATH | — | 46.4% |
| LiveBench Math | — | 94.5% |
| LMArena Math | — | 1447 |
| FrontierMath (Feb 2025 set) | — | 31% |
| FrontierMath Tier 4 (v1) | — | 12.5% |
Knowledge Not comparable
Aion 3.5: —, GPT-5.1: 50.6 (#71)
| Benchmark | Aion 3.5 | GPT-5.1 |
|---|---|---|
| GPQA Diamond | — | 87.6% |
| Humanity's Last Exam | — | 23.7% |
| SimpleQA Verified | — | 48% |
| MMLU-Pro | — | 57.9% |
| Vectara Hallucination Rate | — | 10.9% |
| GPQA (HELM) | — | 44.2% |
| LMArena Expert | — | 1470 |
Multimodal Not comparable
Aion 3.5: —, GPT-5.1: 44.8 (#19)
| Benchmark | Aion 3.5 | GPT-5.1 |
|---|---|---|
| LMArena Vision | — | 1250 |
| VPCT | — | 58.7% |
| LMArena Document | — | 1403 |
Multilingual Not comparable
Aion 3.5: —, GPT-5.1: 53.8 (#56)
| Benchmark | Aion 3.5 | GPT-5.1 |
|---|---|---|
| LMArena Non-English | — | 1431 |
| LMArena Chinese | — | 1495 |
| LMArena French | — | 1450 |
| LMArena German | — | 1438 |
| LMArena Japanese | — | 1453 |
| LMArena Korean | — | 1401 |
| LMArena Russian | — | 1435 |
| LMArena Spanish | — | 1433 |
Instruction Following Not comparable
Aion 3.5: —, GPT-5.1: 83.9 (#1)
| Benchmark | Aion 3.5 | GPT-5.1 |
|---|---|---|
| LiveBench Instruction Following | — | 93.3% |
| IFEval | — | 93.5% |
| LMArena Instruction Following | — | 1443 |
Long Context Not comparable
Aion 3.5: —, GPT-5.1: 47.6 (#14)
| Benchmark | Aion 3.5 | GPT-5.1 |
|---|---|---|
| CL-bench | — | 23.7% |
| CL-bench Life | — | 17.3% |
| LMArena Longer Query | — | 1447 |
Writing & Preference Aion 3.5 leads
Aion 3.5: 74.9, GPT-5.1: 64.5 (#55)
| Benchmark | Aion 3.5 | GPT-5.1 |
|---|---|---|
| LMArena Text | — | 1443 |
| LMArena Creative Writing | — | 1427 |
| EQ-Bench Creative Writing | 1929 | — |
| WildBench | — | 86.3% |
| LMArena Multi-Turn | — | 1450 |
| LiveBench Language | — | 80.2% |
Frequently asked questions
Is Aion 3.5 better than GPT-5.1?
GPT-5.1 has enough public results to be ranked (#53); Aion 3.5 does not yet, so treat this comparison as directional.
Which is cheaper, Aion 3.5 or GPT-5.1?
GPT-5.1 is cheaper. It lists at $1.25 per million input tokens and $10 per million output tokens; Aion 3.5 lists at $3 and $6.
Which has the bigger context window?
GPT-5.1 does, with 400K tokens against 262K.
How many benchmarks do Aion 3.5 and GPT-5.1 share?
0 benchmarks have published results for both models. Aion 3.5 has 1 scored results on Noometry and GPT-5.1 has 63.