# GPT-5.5 Instant vs Step 3

> GPT-5.5 Instant is the stronger model overall, scoring 42.7 to 40.5 on the Noometry Index.

- Canonical page: https://noometry.com/compare/gpt-5-5-instant-vs-step-3
- Last updated: 2026-10-10
- Shared benchmarks: 16

## Summary

- They share 16 benchmarks with published results for both. GPT-5.5 Instant scores higher in 7 categories and Step 3 in 2 categories; 9 gaps are clear of the uncertainty.
- The widest gap is in knowledge, where GPT-5.5 Instant leads 48.9 to 36.8.
- Step 3 has downloadable open weights; the other is API-only.

## Snapshot

| | GPT-5.5 Instant | Step 3 |
|---|---|---|
| Provider | OpenAI | StepFun |
| Noometry Index | 42.7 | 40.5 |
| Rank | 110 | 149 |
| Context | — | — |
| Input $/M | — | — |
| Output $/M | — | — |
| Weights | Proprietary | Open |

## Coding

- GPT-5.5 Instant: 44.3 (#74)
- Step 3: 40.1 (#147)

| Benchmark | GPT-5.5 Instant | Step 3 |
|---|---|---|
| LMArena Coding | 1433 | 1367 |
| SciCode | 48.6% | — |

## Reasoning

- GPT-5.5 Instant: 24.9 (#155)
- Step 3: 28.4 (#105)

| Benchmark | GPT-5.5 Instant | Step 3 |
|---|---|---|
| LMArena Hard Prompts | 1426 | 1355 |
| Kagi LLM Benchmark | — | 62.3% |
| CritPt | 0% | — |
| Chess Puzzles | 12% | — |
| Epoch Capabilities Index | 142.52 | — |

## Math

- GPT-5.5 Instant: 26.5 (#259)
- Step 3: 37.6 (#148)

| Benchmark | GPT-5.5 Instant | Step 3 |
|---|---|---|
| LMArena Math | 1420 | 1366 |
| FrontierMath (Tiers 1-3) | 26.3% | — |
| FrontierMath Tier 4 | 2.4% | — |
| OTIS Mock AIME 2024-2025 | 68.1% | — |

## Knowledge

- GPT-5.5 Instant: 48.9 (#74)
- Step 3: 36.8 (#164)

| Benchmark | GPT-5.5 Instant | Step 3 |
|---|---|---|
| LMArena Expert | 1409 | 1333 |
| GPQA Diamond | 82.5% | — |

## Multimodal

- GPT-5.5 Instant: 40.0 (#52)
- Step 3: 35.5 (#86)

| Benchmark | GPT-5.5 Instant | Step 3 |
|---|---|---|
| LMArena Vision | 1250 | 1177 |
| LMArena Document | 1403 | — |

## Multilingual

- GPT-5.5 Instant: 52.8 (#80)
- Step 3: 46.3 (#159)

| Benchmark | GPT-5.5 Instant | Step 3 |
|---|---|---|
| LMArena Non-English | 1417 | 1327 |
| LMArena Chinese | 1456 | 1397 |
| LMArena German | 1411 | 1371 |
| LMArena Korean | 1392 | 1269 |
| LMArena Russian | 1431 | 1331 |
| LMArena Spanish | 1429 | 1371 |
| LMArena French | 1428 | — |
| LMArena Japanese | 1408 | — |

## Instruction Following

- GPT-5.5 Instant: 74.2 (#100)
- Step 3: 70.4 (#164)

| Benchmark | GPT-5.5 Instant | Step 3 |
|---|---|---|
| LMArena Instruction Following | 1406 | 1332 |

## Long Context

- GPT-5.5 Instant: 43.4 (#96)
- Step 3: 40.3 (#157)

| Benchmark | GPT-5.5 Instant | Step 3 |
|---|---|---|
| LMArena Longer Query | 1422 | 1326 |

## Writing & Preference

- GPT-5.5 Instant: 61.8 (#85)
- Step 3: 54.3 (#151)

| Benchmark | GPT-5.5 Instant | Step 3 |
|---|---|---|
| LMArena Text | 1419 | 1350 |
| LMArena Creative Writing | 1419 | 1321 |
| LMArena Multi-Turn | 1433 | 1341 |

## FAQ

### Is GPT-5.5 Instant better than Step 3?

GPT-5.5 Instant is the stronger model overall, scoring 42.7 to 40.5 on the Noometry Index.

### Is GPT-5.5 Instant or Step 3 better for coding?

GPT-5.5 Instant scores higher on coding benchmarks: 44.3 versus 40.1 in the Noometry coding category.

### How many benchmarks do GPT-5.5 Instant and Step 3 share?

16 benchmarks have published results for both models. GPT-5.5 Instant has 27 scored results on Noometry and Step 3 has 17.