# GPT-5.1-Codex vs Qwen1.5 4b Chat

> GPT-5.1-Codex is the stronger model overall, scoring 38.2 to 28.3 on the Noometry Index.

- Canonical page: https://noometry.com/compare/gpt-5-1-codex-vs-qwen1-5-4b-chat
- Last updated: 2026-10-10
- Shared benchmarks: 0

## Summary

- The widest gap is in coding, where GPT-5.1-Codex leads 41.7 to 28.6.
- Qwen1.5 4b Chat has downloadable open weights; the other is API-only.

## Snapshot

| | GPT-5.1-Codex | Qwen1.5 4b Chat |
|---|---|---|
| Provider | OpenAI | Alibaba (Qwen) |
| Noometry Index | 38.2 | 28.3 |
| Rank | 178 | 319 |
| Context | 400K | — |
| Input $/M | $1.25 | — |
| Output $/M | $10 | — |
| Weights | Proprietary | Open |

## Coding

- GPT-5.1-Codex: 41.7 (#107)
- Qwen1.5 4b Chat: 28.6 (#305)

| Benchmark | GPT-5.1-Codex | Qwen1.5 4b Chat |
|---|---|---|
| SWE-bench Verified (bash only) | 66% | — |
| LMArena WebDev | 1337 | — |
| LMArena Coding | — | 999 |
| ALE-Bench | 1,245 | — |

## Agentic & Tool Use

- GPT-5.1-Codex: 37.8 (#32)
- Qwen1.5 4b Chat: —

| Benchmark | GPT-5.1-Codex | Qwen1.5 4b Chat |
|---|---|---|
| Terminal-Bench | 60.4% | — |
| METR Time Horizons | 70.8% | — |

## Reasoning

- GPT-5.1-Codex: —
- Qwen1.5 4b Chat: 17.7 (#277)

| Benchmark | GPT-5.1-Codex | Qwen1.5 4b Chat |
|---|---|---|
| LMArena Hard Prompts | — | 976 |

## Math

- GPT-5.1-Codex: 29.3 (#218)
- Qwen1.5 4b Chat: 27.9 (#233)

| Benchmark | GPT-5.1-Codex | Qwen1.5 4b Chat |
|---|---|---|
| ProofBench | 9% | — |
| LMArena Math | — | 1026 |

## Knowledge

- GPT-5.1-Codex: —
- Qwen1.5 4b Chat: 26.2 (#252)

| Benchmark | GPT-5.1-Codex | Qwen1.5 4b Chat |
|---|---|---|
| LMArena Expert | — | 980 |

## Multilingual

- GPT-5.1-Codex: —
- Qwen1.5 4b Chat: 24.2 (#285)

| Benchmark | GPT-5.1-Codex | Qwen1.5 4b Chat |
|---|---|---|
| LMArena Non-English | — | 979 |
| LMArena Chinese | — | 1024 |
| LMArena German | — | 902 |
| LMArena Russian | — | 952 |

## Instruction Following

- GPT-5.1-Codex: —
- Qwen1.5 4b Chat: 49.3 (#295)

| Benchmark | GPT-5.1-Codex | Qwen1.5 4b Chat |
|---|---|---|
| LMArena Instruction Following | — | 979 |

## Long Context

- GPT-5.1-Codex: —
- Qwen1.5 4b Chat: 30.1 (#285)

| Benchmark | GPT-5.1-Codex | Qwen1.5 4b Chat |
|---|---|---|
| LMArena Longer Query | — | 988 |

## Writing & Preference

- GPT-5.1-Codex: —
- Qwen1.5 4b Chat: 23.9 (#304)

| Benchmark | GPT-5.1-Codex | Qwen1.5 4b Chat |
|---|---|---|
| LMArena Text | — | 997 |
| LMArena Creative Writing | — | 969 |
| LMArena Multi-Turn | — | 977 |

## FAQ

### Is GPT-5.1-Codex better than Qwen1.5 4b Chat?

GPT-5.1-Codex is the stronger model overall, scoring 38.2 to 28.3 on the Noometry Index.

### Is GPT-5.1-Codex or Qwen1.5 4b Chat better for coding?

GPT-5.1-Codex scores higher on coding benchmarks: 41.7 versus 28.6 in the Noometry coding category.

### How many benchmarks do GPT-5.1-Codex and Qwen1.5 4b Chat share?

0 benchmarks have published results for both models. GPT-5.1-Codex has 6 scored results on Noometry and Qwen1.5 4b Chat has 13.