# gpt-oss-20b vs Solar Pro4

> Solar Pro4 is the stronger model overall, scoring 41.5 to 32.1 on the Noometry Index. gpt-oss-20b costs 15× less per token, which makes it the better buy when Solar Pro4's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/gpt-oss-20b-vs-solar-pro4
- Last updated: 2026-10-10
- Shared benchmarks: 16

## Summary

- They share 16 benchmarks with published results for both. gpt-oss-20b scores higher in 1 category and Solar Pro4 in 7 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in writing & preference, where Solar Pro4 leads 56.7 to 35.8.
- gpt-oss-20b is cheaper at $0.018 / $0.09 per million input/output tokens, against $0.30 / $1.20 for Solar Pro4.
- Solar Pro4 accepts more context: 524K tokens versus 131K.
- gpt-oss-20b has downloadable open weights; the other is API-only.

## Snapshot

| | gpt-oss-20b | Solar Pro4 |
|---|---|---|
| Provider | OpenAI | Upstage |
| Noometry Index | 32.1 | 41.5 |
| Rank | 249 | 123 |
| Context | 131K | 524K |
| Input $/M | $0.018 | $0.30 |
| Output $/M | $0.09 | $1.20 |
| Weights | Open | Proprietary |

## Coding

- gpt-oss-20b: 37.1 (#185)
- Solar Pro4: 39.9 (#135)

| Benchmark | gpt-oss-20b | Solar Pro4 |
|---|---|---|
| LMArena Coding | 1307 | 1439 |
| LMArena WebDev | — | 1371 |
| SciCode | 34.4% | — |
| WeirdML | 40.9% | — |
| ALE-Bench | 566.05 | — |

## Agentic & Tool Use

- gpt-oss-20b: 9.2 (#146)
- Solar Pro4: —

| Benchmark | gpt-oss-20b | Solar Pro4 |
|---|---|---|
| Terminal-Bench | 3.4% | — |

## Reasoning

- gpt-oss-20b: 18.8 (#251)
- Solar Pro4: 27.3 (#107)

| Benchmark | gpt-oss-20b | Solar Pro4 |
|---|---|---|
| LMArena Hard Prompts | 1274 | 1398 |
| Kagi LLM Benchmark | 53.2% | — |
| CritPt | 1.4% | — |
| Chess Puzzles | 4% | — |
| DTBench | 68% | — |
| LMCA | 14.5% | — |
| Epoch Capabilities Index | 137.81 | — |

## Math

- gpt-oss-20b: 37.6 (#93)
- Solar Pro4: 36.1 (#129)

| Benchmark | gpt-oss-20b | Solar Pro4 |
|---|---|---|
| LMArena Math | 1317 | 1418 |
| OTIS Mock AIME 2024-2025 | 65.3% | — |
| Omni-MATH | 56.5% | — |

## Knowledge

- gpt-oss-20b: 34.6 (#186)
- Solar Pro4: 39.0 (#128)

| Benchmark | gpt-oss-20b | Solar Pro4 |
|---|---|---|
| LMArena Expert | 1258 | 1421 |
| GPQA Diamond | 60.8% | — |
| MMLU-Pro | 74% | — |
| GPQA (HELM) | 59.4% | — |

## Multilingual

- gpt-oss-20b: 42.4 (#192)
- Solar Pro4: 49.0 (#134)

| Benchmark | gpt-oss-20b | Solar Pro4 |
|---|---|---|
| LMArena Non-English | 1269 | 1362 |
| LMArena Chinese | 1311 | 1417 |
| LMArena German | 1249 | 1351 |
| LMArena Japanese | 1245 | 1300 |
| LMArena Korean | 1239 | 1383 |
| LMArena Russian | 1279 | 1360 |
| LMArena Spanish | 1267 | 1408 |
| LMArena French | — | 1403 |

## Instruction Following

- gpt-oss-20b: 62.0 (#235)
- Solar Pro4: 72.8 (#128)

| Benchmark | gpt-oss-20b | Solar Pro4 |
|---|---|---|
| LMArena Instruction Following | 1236 | 1376 |
| IFEval | 73.2% | — |

## Long Context

- gpt-oss-20b: 37.9 (#203)
- Solar Pro4: 42.0 (#125)

| Benchmark | gpt-oss-20b | Solar Pro4 |
|---|---|---|
| LMArena Longer Query | 1251 | 1379 |

## Writing & Preference

- gpt-oss-20b: 35.8 (#260)
- Solar Pro4: 56.7 (#133)

| Benchmark | gpt-oss-20b | Solar Pro4 |
|---|---|---|
| LMArena Text | 1288 | 1386 |
| LMArena Creative Writing | 1201 | 1313 |
| LMArena Multi-Turn | 1268 | 1391 |
| EQ-Bench Creative Writing | 666 | — |
| WildBench | 73.7% | — |

## FAQ

### Is gpt-oss-20b better than Solar Pro4?

Solar Pro4 is the stronger model overall, scoring 41.5 to 32.1 on the Noometry Index. gpt-oss-20b costs 15× less per token, which makes it the better buy when Solar Pro4's lead doesn't matter for your workload.

### Which is cheaper, gpt-oss-20b or Solar Pro4?

gpt-oss-20b is cheaper. It lists at $0.018 per million input tokens and $0.09 per million output tokens; Solar Pro4 lists at $0.30 and $1.20.

### Is gpt-oss-20b or Solar Pro4 better for coding?

Solar Pro4 scores higher on coding benchmarks: 39.9 versus 37.1 in the Noometry coding category.

### Which has the bigger context window?

Solar Pro4 does, with 524K tokens against 131K.

### How many benchmarks do gpt-oss-20b and Solar Pro4 share?

16 benchmarks have published results for both models. gpt-oss-20b has 34 scored results on Noometry and Solar Pro4 has 18.