# GPT-5-Codex vs Qwen3.5 27B

> Qwen3.5 27B is the stronger model overall, scoring 41.4 to 37.3 on the Noometry Index.

- Canonical page: https://noometry.com/compare/gpt-5-codex-vs-qwen3-5-27b
- Last updated: 2026-10-10
- Shared benchmarks: 1

## Summary

- They share 1 benchmark with published results for both. GPT-5-Codex scores higher in 2 categories and Qwen3.5 27B in 0 categories; 2 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where GPT-5-Codex leads 30.0 to 26.6.
- The biggest single-benchmark swing is WeirdML: 54.5% for GPT-5-Codex and 39.5% for Qwen3.5 27B.
- Qwen3.5 27B is cheaper at $0.30 / $2.40 per million input/output tokens, against $1.25 / $10 for GPT-5-Codex.
- GPT-5-Codex accepts more context: 400K tokens versus 262K.
- Qwen3.5 27B has downloadable open weights; the other is API-only.

## Snapshot

| | GPT-5-Codex | Qwen3.5 27B |
|---|---|---|
| Provider | OpenAI | Alibaba (Qwen) |
| Noometry Index | 37.3 | 41.4 |
| Rank | 190 | 127 |
| Context | 400K | 262K |
| Input $/M | $1.25 | $0.30 |
| Output $/M | $10 | $2.40 |
| Weights | Proprietary | Open |

## Coding

- GPT-5-Codex: 41.9 (#100)
- Qwen3.5 27B: 38.6 (#159)

| Benchmark | GPT-5-Codex | Qwen3.5 27B |
|---|---|---|
| WeirdML | 54.5% | 39.5% |
| LMArena WebDev | — | 1357 |
| LMArena Coding | — | 1427 |
| ALE-Bench | — | 349.45 |

## Agentic & Tool Use

- GPT-5-Codex: 30.8 (#66)
- Qwen3.5 27B: —

| Benchmark | GPT-5-Codex | Qwen3.5 27B |
|---|---|---|
| Terminal-Bench | 44.3% | — |
| Vending-Bench 2 | — | 201.98 |

## Reasoning

- GPT-5-Codex: 30.0 (#80)
- Qwen3.5 27B: 26.6 (#116)

| Benchmark | GPT-5-Codex | Qwen3.5 27B |
|---|---|---|
| Kagi LLM Benchmark | 70.3% | — |
| NYT Connections (extended) | — | 47.9% |
| Thematic Generalization | — | 45.5% |
| LMArena Hard Prompts | — | 1414 |
| DTBench | — | 82.4% |
| LMCA | — | 34% |

## Math

- GPT-5-Codex: —
- Qwen3.5 27B: 36.8 (#103)

| Benchmark | GPT-5-Codex | Qwen3.5 27B |
|---|---|---|
| MathArena Final-Answer Competitions | — | 56.7% |
| LMArena Math | — | 1428 |

## Knowledge

- GPT-5-Codex: —
- Qwen3.5 27B: 37.4 (#149)

| Benchmark | GPT-5-Codex | Qwen3.5 27B |
|---|---|---|
| Vectara Hallucination Rate | — | 12.1% |
| LMArena Expert | — | 1428 |

## Multimodal

- GPT-5-Codex: —
- Qwen3.5 27B: 38.7 (#56)

| Benchmark | GPT-5-Codex | Qwen3.5 27B |
|---|---|---|
| LMArena Vision | — | 1240 |

## Multilingual

- GPT-5-Codex: —
- Qwen3.5 27B: 51.0 (#112)

| Benchmark | GPT-5-Codex | Qwen3.5 27B |
|---|---|---|
| LMArena Non-English | — | 1390 |
| LMArena Chinese | — | 1478 |
| LMArena French | — | 1409 |
| LMArena German | — | 1393 |
| LMArena Japanese | — | 1345 |
| LMArena Korean | — | 1359 |
| LMArena Russian | — | 1389 |
| LMArena Spanish | — | 1408 |

## Instruction Following

- GPT-5-Codex: —
- Qwen3.5 27B: 73.7 (#114)

| Benchmark | GPT-5-Codex | Qwen3.5 27B |
|---|---|---|
| LMArena Instruction Following | — | 1393 |

## Long Context

- GPT-5-Codex: —
- Qwen3.5 27B: 43.1 (#103)

| Benchmark | GPT-5-Codex | Qwen3.5 27B |
|---|---|---|
| LMArena Longer Query | — | 1413 |

## Writing & Preference

- GPT-5-Codex: —
- Qwen3.5 27B: 59.5 (#106)

| Benchmark | GPT-5-Codex | Qwen3.5 27B |
|---|---|---|
| LMArena Text | — | 1409 |
| LMArena Creative Writing | — | 1362 |
| LMArena Multi-Turn | — | 1410 |

## FAQ

### Is GPT-5-Codex better than Qwen3.5 27B?

Qwen3.5 27B is the stronger model overall, scoring 41.4 to 37.3 on the Noometry Index.

### Which is cheaper, GPT-5-Codex or Qwen3.5 27B?

Qwen3.5 27B is cheaper. It lists at $0.30 per million input tokens and $2.40 per million output tokens; GPT-5-Codex lists at $1.25 and $10.

### Is GPT-5-Codex or Qwen3.5 27B better for coding?

GPT-5-Codex scores higher on coding benchmarks: 41.9 versus 38.6 in the Noometry coding category.

### Which has the bigger context window?

GPT-5-Codex does, with 400K tokens against 262K.

### How many benchmarks do GPT-5-Codex and Qwen3.5 27B share?

1 benchmark has published results for both models. GPT-5-Codex has 3 scored results on Noometry and Qwen3.5 27B has 28.