# gpt-oss-20b vs MiMo-V2.5

> MiMo-V2.5 is the stronger model overall, scoring 43.4 to 32.5 on the Noometry Index. gpt-oss-20b costs 4.9× less per token, which makes it the better buy when MiMo-V2.5's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/gpt-oss-20b-vs-mimo-v2-5
- Last updated: 2026-10-11
- Shared benchmarks: 19

## Summary

- They share 19 benchmarks with published results for both. gpt-oss-20b scores higher in 1 category and MiMo-V2.5 in 7 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in writing & preference, where MiMo-V2.5 leads 61.6 to 35.5.
- The biggest single-benchmark swing is SciCode: 34.4% for gpt-oss-20b and 43.1% for MiMo-V2.5.
- gpt-oss-20b is cheaper at $0.018 / $0.09 per million input/output tokens, against $0.14 / $0.28 for MiMo-V2.5.
- MiMo-V2.5 accepts more context: 1.05M tokens versus 131K.

## Snapshot

| | gpt-oss-20b | MiMo-V2.5 |
|---|---|---|
| Provider | OpenAI | Xiaomi |
| Noometry Index | 32.5 | 43.4 |
| Rank | 255 | 93 |
| Context | 131K | 1.05M |
| Input $/M | $0.018 | $0.14 |
| Output $/M | $0.09 | $0.28 |
| Weights | Open | Open |

## Coding

- gpt-oss-20b: 37.6 (#192)
- MiMo-V2.5: 43.9 (#81)

| Benchmark | gpt-oss-20b | MiMo-V2.5 |
|---|---|---|
| SciCode | 34.4% | 43.1% |
| LMArena Coding | 1306 | 1469 |
| ALE-Bench | 566.05 | 513.95 |
| LMArena WebDev | — | 1438 |
| WeirdML | 40.9% | — |

## Agentic & Tool Use

- gpt-oss-20b: 9.3 (#154)
- MiMo-V2.5: —

| Benchmark | gpt-oss-20b | MiMo-V2.5 |
|---|---|---|
| Terminal-Bench | 3.4% | — |

## Reasoning

- gpt-oss-20b: 19.3 (#261)
- MiMo-V2.5: 28.6 (#101)

| Benchmark | gpt-oss-20b | MiMo-V2.5 |
|---|---|---|
| CritPt | 1.4% | 3.7% |
| LMArena Hard Prompts | 1274 | 1450 |
| Kagi LLM Benchmark | 53.2% | — |
| Chess Puzzles | 4% | — |
| DTBench | 68% | — |
| LMCA | 14.5% | — |
| Epoch Capabilities Index | 137.82 | — |

## Math

- gpt-oss-20b: 39.4 (#103)
- MiMo-V2.5: 36.8 (#163)

| Benchmark | gpt-oss-20b | MiMo-V2.5 |
|---|---|---|
| LMArena Math | 1317 | 1436 |
| OTIS Mock AIME 2024-2025 | 65.3% | — |
| ProofBench | — | 16% |
| Omni-MATH | 56.5% | — |

## Knowledge

- gpt-oss-20b: 34.6 (#195)
- MiMo-V2.5: 40.8 (#115)

| Benchmark | gpt-oss-20b | MiMo-V2.5 |
|---|---|---|
| LMArena Expert | 1258 | 1460 |
| GPQA Diamond | 60.8% | — |
| MMLU-Pro | 74% | — |
| GPQA (HELM) | 59.4% | — |

## Multimodal

- gpt-oss-20b: —
- MiMo-V2.5: 39.8 (#54)

| Benchmark | gpt-oss-20b | MiMo-V2.5 |
|---|---|---|
| LMArena Vision | — | 1247 |

## Multilingual

- gpt-oss-20b: 42.2 (#197)
- MiMo-V2.5: 51.9 (#99)

| Benchmark | gpt-oss-20b | MiMo-V2.5 |
|---|---|---|
| LMArena Non-English | 1268 | 1404 |
| LMArena Chinese | 1314 | 1468 |
| LMArena German | 1255 | 1421 |
| LMArena Japanese | 1244 | 1306 |
| LMArena Korean | 1236 | 1363 |
| LMArena Russian | 1278 | 1395 |
| LMArena Spanish | 1267 | 1416 |
| LMArena French | — | 1447 |

## Instruction Following

- gpt-oss-20b: 61.8 (#240)
- MiMo-V2.5: 75.5 (#60)

| Benchmark | gpt-oss-20b | MiMo-V2.5 |
|---|---|---|
| LMArena Instruction Following | 1236 | 1434 |
| IFEval | 73.2% | — |

## Long Context

- gpt-oss-20b: 37.9 (#209)
- MiMo-V2.5: 44.2 (#73)

| Benchmark | gpt-oss-20b | MiMo-V2.5 |
|---|---|---|
| LMArena Longer Query | 1250 | 1445 |

## Writing & Preference

- gpt-oss-20b: 35.5 (#265)
- MiMo-V2.5: 61.6 (#86)

| Benchmark | gpt-oss-20b | MiMo-V2.5 |
|---|---|---|
| LMArena Text | 1287 | 1428 |
| LMArena Creative Writing | 1201 | 1393 |
| LMArena Multi-Turn | 1268 | 1445 |
| EQ-Bench Creative Writing | 666 | — |
| WildBench | 73.7% | — |

## FAQ

### Is gpt-oss-20b better than MiMo-V2.5?

MiMo-V2.5 is the stronger model overall, scoring 43.4 to 32.5 on the Noometry Index. gpt-oss-20b costs 4.9× less per token, which makes it the better buy when MiMo-V2.5's lead doesn't matter for your workload.

### Which is cheaper, gpt-oss-20b or MiMo-V2.5?

gpt-oss-20b is cheaper. It lists at $0.018 per million input tokens and $0.09 per million output tokens; MiMo-V2.5 lists at $0.14 and $0.28.

### Is gpt-oss-20b or MiMo-V2.5 better for coding?

MiMo-V2.5 scores higher on coding benchmarks: 43.9 versus 37.6 in the Noometry coding category.

### Which has the bigger context window?

MiMo-V2.5 does, with 1.05M tokens against 131K.

### How many benchmarks do gpt-oss-20b and MiMo-V2.5 share?

19 benchmarks have published results for both models. gpt-oss-20b has 34 scored results on Noometry and MiMo-V2.5 has 23.