# GPT-5.1-Codex vs Yi-Lightning

> GPT-5.1-Codex is the stronger model overall, scoring 38.6 to 37.1 on the Noometry Index.

- Canonical page: https://noometry.com/compare/gpt-5-1-codex-vs-yi-lightning
- Last updated: 2026-10-11
- Shared benchmarks: 0

## Summary

- The widest gap is in coding, where GPT-5.1-Codex leads 41.9 to 27.4.

## Snapshot

| | GPT-5.1-Codex | Yi-Lightning |
|---|---|---|
| Provider | OpenAI | 01.AI |
| Noometry Index | 38.6 | 37.1 |
| Rank | 186 | 209 |
| Context | 400K | — |
| Input $/M | $1.25 | — |
| Output $/M | $10 | — |
| Weights | Proprietary | Proprietary |

## Coding

- GPT-5.1-Codex: 41.9 (#116)
- Yi-Lightning: 27.4 (#320)

| Benchmark | GPT-5.1-Codex | Yi-Lightning |
|---|---|---|
| SWE-bench Verified (bash only) | 66% | — |
| Aider Polyglot | — | 12.9% |
| LMArena WebDev | 1337 | — |
| LMArena Coding | — | 1312 |
| ALE-Bench | 1,245 | — |

## Agentic & Tool Use

- GPT-5.1-Codex: 38.0 (#33)
- Yi-Lightning: —

| Benchmark | GPT-5.1-Codex | Yi-Lightning |
|---|---|---|
| Terminal-Bench | 60.4% | — |
| METR Time Horizons | 70.8% | — |

## Reasoning

- GPT-5.1-Codex: —
- Yi-Lightning: 25.9 (#139)

| Benchmark | GPT-5.1-Codex | Yi-Lightning |
|---|---|---|
| LMArena Hard Prompts | — | 1302 |

## Math

- GPT-5.1-Codex: 30.3 (#235)
- Yi-Lightning: 36.2 (#172)

| Benchmark | GPT-5.1-Codex | Yi-Lightning |
|---|---|---|
| ProofBench | 9% | — |
| LMArena Math | — | 1300 |

## Knowledge

- GPT-5.1-Codex: —
- Yi-Lightning: 35.4 (#185)

| Benchmark | GPT-5.1-Codex | Yi-Lightning |
|---|---|---|
| LMArena Expert | — | 1286 |

## Multilingual

- GPT-5.1-Codex: —
- Yi-Lightning: 42.2 (#196)

| Benchmark | GPT-5.1-Codex | Yi-Lightning |
|---|---|---|
| LMArena Non-English | — | 1269 |
| LMArena Chinese | — | 1320 |
| LMArena French | — | 1305 |
| LMArena German | — | 1267 |
| LMArena Japanese | — | 1228 |
| LMArena Korean | — | 1192 |
| LMArena Russian | — | 1255 |
| LMArena Spanish | — | 1315 |

## Instruction Following

- GPT-5.1-Codex: —
- Yi-Lightning: 67.4 (#196)

| Benchmark | GPT-5.1-Codex | Yi-Lightning |
|---|---|---|
| LMArena Instruction Following | — | 1278 |

## Long Context

- GPT-5.1-Codex: —
- Yi-Lightning: 39.4 (#181)

| Benchmark | GPT-5.1-Codex | Yi-Lightning |
|---|---|---|
| LMArena Longer Query | — | 1297 |

## Writing & Preference

- GPT-5.1-Codex: —
- Yi-Lightning: 50.2 (#184)

| Benchmark | GPT-5.1-Codex | Yi-Lightning |
|---|---|---|
| LMArena Text | — | 1302 |
| LMArena Creative Writing | — | 1280 |
| LMArena Multi-Turn | — | 1311 |

## FAQ

### Is GPT-5.1-Codex better than Yi-Lightning?

GPT-5.1-Codex is the stronger model overall, scoring 38.6 to 37.1 on the Noometry Index.

### Is GPT-5.1-Codex or Yi-Lightning better for coding?

GPT-5.1-Codex scores higher on coding benchmarks: 41.9 versus 27.4 in the Noometry coding category.

### How many benchmarks do GPT-5.1-Codex and Yi-Lightning share?

0 benchmarks have published results for both models. GPT-5.1-Codex has 6 scored results on Noometry and Yi-Lightning has 18.