# DeepSeek-V2.5 (Sep 2024) vs GPT-5.1-Codex

> GPT-5.1-Codex is the stronger model overall, scoring 38.6 to 37.6 on the Noometry Index.

- Canonical page: https://noometry.com/compare/deepseek-v2-5-vs-gpt-5-1-codex
- Last updated: 2026-10-11
- Shared benchmarks: 0

## Summary

- The widest gap is in coding, where GPT-5.1-Codex leads 41.9 to 31.7.
- DeepSeek-V2.5 (Sep 2024) has downloadable open weights; the other is API-only.

## Snapshot

| | DeepSeek-V2.5 (Sep 2024) | GPT-5.1-Codex |
|---|---|---|
| Provider | DeepSeek | OpenAI |
| Noometry Index | 37.6 | 38.6 |
| Rank | 200 | 186 |
| Context | — | 400K |
| Input $/M | — | $1.25 |
| Output $/M | — | $10 |
| Weights | Open | Proprietary |

## Coding

- DeepSeek-V2.5 (Sep 2024): 31.7 (#281)
- GPT-5.1-Codex: 41.9 (#116)

| Benchmark | DeepSeek-V2.5 (Sep 2024) | GPT-5.1-Codex |
|---|---|---|
| SWE-bench Verified (bash only) | — | 66% |
| Aider Polyglot | 17.8% | — |
| LMArena WebDev | — | 1337 |
| BigCodeBench Instruct | 48.6% | — |
| LMArena Coding | 1309 | — |
| BigCodeBench Complete | 53.2% | — |
| ALE-Bench | — | 1,245 |
| HumanEval+ | 83.5% | — |
| MBPP+ | 74.1% | — |

## Agentic & Tool Use

- DeepSeek-V2.5 (Sep 2024): —
- GPT-5.1-Codex: 38.0 (#33)

| Benchmark | DeepSeek-V2.5 (Sep 2024) | GPT-5.1-Codex |
|---|---|---|
| Terminal-Bench | — | 60.4% |
| METR Time Horizons | — | 70.8% |

## Reasoning

- DeepSeek-V2.5 (Sep 2024): 25.6 (#145)
- GPT-5.1-Codex: —

| Benchmark | DeepSeek-V2.5 (Sep 2024) | GPT-5.1-Codex |
|---|---|---|
| LMArena Hard Prompts | 1289 | — |

## Math

- DeepSeek-V2.5 (Sep 2024): 35.9 (#177)
- GPT-5.1-Codex: 30.3 (#235)

| Benchmark | DeepSeek-V2.5 (Sep 2024) | GPT-5.1-Codex |
|---|---|---|
| ProofBench | — | 9% |
| LMArena Math | 1288 | — |

## Knowledge

- DeepSeek-V2.5 (Sep 2024): 34.8 (#193)
- GPT-5.1-Codex: —

| Benchmark | DeepSeek-V2.5 (Sep 2024) | GPT-5.1-Codex |
|---|---|---|
| LMArena Expert | 1266 | — |

## Multilingual

- DeepSeek-V2.5 (Sep 2024): 42.5 (#193)
- GPT-5.1-Codex: —

| Benchmark | DeepSeek-V2.5 (Sep 2024) | GPT-5.1-Codex |
|---|---|---|
| LMArena Non-English | 1273 | — |
| LMArena Chinese | 1318 | — |
| LMArena French | 1289 | — |
| LMArena German | 1258 | — |
| LMArena Japanese | 1228 | — |
| LMArena Korean | 1209 | — |
| LMArena Russian | 1289 | — |
| LMArena Spanish | 1248 | — |

## Instruction Following

- DeepSeek-V2.5 (Sep 2024): 67.5 (#194)
- GPT-5.1-Codex: —

| Benchmark | DeepSeek-V2.5 (Sep 2024) | GPT-5.1-Codex |
|---|---|---|
| LMArena Instruction Following | 1280 | — |

## Long Context

- DeepSeek-V2.5 (Sep 2024): 39.5 (#174)
- GPT-5.1-Codex: —

| Benchmark | DeepSeek-V2.5 (Sep 2024) | GPT-5.1-Codex |
|---|---|---|
| LMArena Longer Query | 1301 | — |

## Writing & Preference

- DeepSeek-V2.5 (Sep 2024): 49.8 (#187)
- GPT-5.1-Codex: —

| Benchmark | DeepSeek-V2.5 (Sep 2024) | GPT-5.1-Codex |
|---|---|---|
| LMArena Text | 1294 | — |
| LMArena Creative Writing | 1285 | — |
| LMArena Multi-Turn | 1297 | — |

## FAQ

### Is DeepSeek-V2.5 (Sep 2024) better than GPT-5.1-Codex?

GPT-5.1-Codex is the stronger model overall, scoring 38.6 to 37.6 on the Noometry Index.

### Is DeepSeek-V2.5 (Sep 2024) or GPT-5.1-Codex better for coding?

GPT-5.1-Codex scores higher on coding benchmarks: 41.9 versus 31.7 in the Noometry coding category.

### How many benchmarks do DeepSeek-V2.5 (Sep 2024) and GPT-5.1-Codex share?

0 benchmarks have published results for both models. DeepSeek-V2.5 (Sep 2024) has 22 scored results on Noometry and GPT-5.1-Codex has 6.