# GPT-5.1-Codex vs Yi-34B

> GPT-5.1-Codex is the stronger model overall, scoring 38.6 to 27.8 on the Noometry Index.

- Canonical page: https://noometry.com/compare/gpt-5-1-codex-vs-yi-34b
- Last updated: 2026-10-11
- Shared benchmarks: 0

## Summary

- The widest gap is in coding, where GPT-5.1-Codex leads 41.9 to 32.3.
- Yi-34B has downloadable open weights; the other is API-only.

## Snapshot

| | GPT-5.1-Codex | Yi-34B |
|---|---|---|
| Provider | OpenAI | 01.AI |
| Noometry Index | 38.6 | 27.8 |
| Rank | 186 | 329 |
| Context | 400K | — |
| Input $/M | $1.25 | — |
| Output $/M | $10 | — |
| Weights | Proprietary | Open |

## Coding

- GPT-5.1-Codex: 41.9 (#116)
- Yi-34B: 32.3 (#274)

| Benchmark | GPT-5.1-Codex | Yi-34B |
|---|---|---|
| SWE-bench Verified (bash only) | 66% | — |
| LMArena WebDev | 1337 | — |
| LMArena Coding | — | 1112 |
| ALE-Bench | 1,245 | — |

## Agentic & Tool Use

- GPT-5.1-Codex: 38.0 (#33)
- Yi-34B: —

| Benchmark | GPT-5.1-Codex | Yi-34B |
|---|---|---|
| Terminal-Bench | 60.4% | — |
| METR Time Horizons | 70.8% | — |

## Reasoning

- GPT-5.1-Codex: —
- Yi-34B: 21.2 (#226)

| Benchmark | GPT-5.1-Codex | Yi-34B |
|---|---|---|
| LMArena Hard Prompts | — | 1104 |
| BIG-Bench Hard | — | 71.7% |
| Epoch Capabilities Index | — | 117.39 |

## Math

- GPT-5.1-Codex: 30.3 (#235)
- Yi-34B: 21.6 (#282)

| Benchmark | GPT-5.1-Codex | Yi-34B |
|---|---|---|
| ProofBench | 9% | — |
| LMArena Math | — | 1114 |
| MATH Level 5 | — | 5.1% |
| GSM8K | — | 76% |

## Knowledge

- GPT-5.1-Codex: —
- Yi-34B: 7.5 (#309)

| Benchmark | GPT-5.1-Codex | Yi-34B |
|---|---|---|
| GPQA Diamond | — | 14.7% |
| LMArena Expert | — | 1061 |
| MMLU | — | 76.3% |

## Multilingual

- GPT-5.1-Codex: —
- Yi-34B: 29.7 (#264)

| Benchmark | GPT-5.1-Codex | Yi-34B |
|---|---|---|
| LMArena Non-English | — | 1079 |
| LMArena Chinese | — | 1176 |
| LMArena French | — | 1081 |
| LMArena German | — | 1042 |
| LMArena Japanese | — | 993 |
| LMArena Korean | — | 959 |
| LMArena Russian | — | 1050 |
| LMArena Spanish | — | 1070 |

## Instruction Following

- GPT-5.1-Codex: —
- Yi-34B: 56.2 (#274)

| Benchmark | GPT-5.1-Codex | Yi-34B |
|---|---|---|
| LMArena Instruction Following | — | 1091 |

## Long Context

- GPT-5.1-Codex: —
- Yi-34B: 33.2 (#264)

| Benchmark | GPT-5.1-Codex | Yi-34B |
|---|---|---|
| LMArena Longer Query | — | 1094 |

## Writing & Preference

- GPT-5.1-Codex: —
- Yi-34B: 34.1 (#273)

| Benchmark | GPT-5.1-Codex | Yi-34B |
|---|---|---|
| LMArena Text | — | 1129 |
| LMArena Creative Writing | — | 1108 |
| LMArena Multi-Turn | — | 1113 |

## FAQ

### Is GPT-5.1-Codex better than Yi-34B?

GPT-5.1-Codex is the stronger model overall, scoring 38.6 to 27.8 on the Noometry Index.

### Is GPT-5.1-Codex or Yi-34B better for coding?

GPT-5.1-Codex scores higher on coding benchmarks: 41.9 versus 32.3 in the Noometry coding category.

### How many benchmarks do GPT-5.1-Codex and Yi-34B share?

0 benchmarks have published results for both models. GPT-5.1-Codex has 6 scored results on Noometry and Yi-34B has 23.