# Grok 4.3 vs Step 3.5 Flash

> Grok 4.3 is the stronger model overall, scoring 43.6 to 41.7 on the Noometry Index. Step 3.5 Flash costs 10× less per token, which makes it the better buy when Grok 4.3's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/grok-4-3-vs-step-3-5-flash
- Last updated: 2026-10-10
- Shared benchmarks: 18

## Summary

- They share 18 benchmarks with published results for both. Grok 4.3 scores higher in 3 categories and Step 3.5 Flash in 5 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Grok 4.3 leads 34.9 to 21.2.
- The biggest single-benchmark swing is NYT Connections (extended): 55.2% for Grok 4.3 and 28.4% for Step 3.5 Flash.
- Step 3.5 Flash is cheaper at $0.10 / $0.30 per million input/output tokens, against $1.25 / $2.50 for Grok 4.3.
- Grok 4.3 accepts more context: 1M tokens versus 256K.
- Step 3.5 Flash has downloadable open weights; the other is API-only.

## Snapshot

| | Grok 4.3 | Step 3.5 Flash |
|---|---|---|
| Provider | xAI | StepFun |
| Noometry Index | 43.6 | 41.7 |
| Rank | 80 | 116 |
| Context | 1M | 256K |
| Input $/M | $1.25 | $0.10 |
| Output $/M | $2.50 | $0.30 |
| Weights | Proprietary | Open |

## Coding

- Grok 4.3: 41.3 (#117)
- Step 3.5 Flash: 41.7 (#106)

| Benchmark | Grok 4.3 | Step 3.5 Flash |
|---|---|---|
| LMArena Coding | 1415 | 1436 |
| LMArena WebDev | 1357 | — |
| SciCode | 47.3% | — |
| WeirdML | 49.9% | — |
| ALE-Bench | 944.17 | — |

## Agentic & Tool Use

- Grok 4.3: 27.6 (#93)
- Step 3.5 Flash: —

| Benchmark | Grok 4.3 | Step 3.5 Flash |
|---|---|---|
| GDP.pdf | 8% | — |
| LMArena Search | 1165 | — |
| Vending-Bench 2 | 35.26 | — |

## Reasoning

- Grok 4.3: 34.9 (#60)
- Step 3.5 Flash: 21.2 (#202)

| Benchmark | Grok 4.3 | Step 3.5 Flash |
|---|---|---|
| NYT Connections (extended) | 55.2% | 28.4% |
| LMArena Hard Prompts | 1397 | 1411 |
| CritPt | 8% | — |
| Chess Puzzles | 25% | — |
| DTBench | 90.7% | — |
| LMCA | 38.3% | — |
| Epoch Capabilities Index | 149.13 | — |
| ForecastBench | 60.3 | — |

## Math

- Grok 4.3: 45.8 (#60)
- Step 3.5 Flash: 40.6 (#77)

| Benchmark | Grok 4.3 | Step 3.5 Flash |
|---|---|---|
| LMArena Math | 1388 | 1408 |
| FrontierMath (Tiers 1-3) | 42.8% | — |
| FrontierMath Tier 4 | 14.6% | — |
| MathArena Final-Answer Competitions | — | 66.8% |
| OTIS Mock AIME 2024-2025 | 93.3% | — |
| ProofBench | 11% | — |

## Knowledge

- Grok 4.3: 52.5 (#57)
- Step 3.5 Flash: 39.0 (#127)

| Benchmark | Grok 4.3 | Step 3.5 Flash |
|---|---|---|
| LMArena Expert | 1385 | 1422 |
| GPQA Diamond | 88.8% | — |
| SimpleQA Verified | 33.2% | — |

## Multimodal

- Grok 4.3: 31.6 (#96)
- Step 3.5 Flash: —

| Benchmark | Grok 4.3 | Step 3.5 Flash |
|---|---|---|
| LMArena Vision | 1231 | — |
| Blueprint-Bench 2 | 0% | — |

## Multilingual

- Grok 4.3: 50.7 (#114)
- Step 3.5 Flash: 50.7 (#115)

| Benchmark | Grok 4.3 | Step 3.5 Flash |
|---|---|---|
| LMArena Non-English | 1385 | 1386 |
| LMArena Chinese | 1423 | 1448 |
| LMArena French | 1412 | 1421 |
| LMArena German | 1395 | 1404 |
| LMArena Japanese | 1379 | 1353 |
| LMArena Korean | 1357 | 1350 |
| LMArena Russian | 1399 | 1385 |
| LMArena Spanish | 1402 | 1419 |

## Instruction Following

- Grok 4.3: 72.3 (#135)
- Step 3.5 Flash: 73.3 (#119)

| Benchmark | Grok 4.3 | Step 3.5 Flash |
|---|---|---|
| LMArena Instruction Following | 1366 | 1385 |

## Long Context

- Grok 4.3: 42.5 (#118)
- Step 3.5 Flash: 42.8 (#112)

| Benchmark | Grok 4.3 | Step 3.5 Flash |
|---|---|---|
| LMArena Longer Query | 1393 | 1402 |

## Writing & Preference

- Grok 4.3: 58.6 (#112)
- Step 3.5 Flash: 59.0 (#108)

| Benchmark | Grok 4.3 | Step 3.5 Flash |
|---|---|---|
| LMArena Text | 1397 | 1403 |
| LMArena Creative Writing | 1380 | 1357 |
| LMArena Multi-Turn | 1406 | 1405 |
| EQ-Bench 4 | 1075 | — |

## FAQ

### Is Grok 4.3 better than Step 3.5 Flash?

Grok 4.3 is the stronger model overall, scoring 43.6 to 41.7 on the Noometry Index. Step 3.5 Flash costs 10× less per token, which makes it the better buy when Grok 4.3's lead doesn't matter for your workload.

### Which is cheaper, Grok 4.3 or Step 3.5 Flash?

Step 3.5 Flash is cheaper. It lists at $0.10 per million input tokens and $0.30 per million output tokens; Grok 4.3 lists at $1.25 and $2.50.

### Is Grok 4.3 or Step 3.5 Flash better for coding?

They score almost the same on coding (41.3 vs 41.7); test both on your own repository before choosing.

### Which has the bigger context window?

Grok 4.3 does, with 1M tokens against 256K.

### How many benchmarks do Grok 4.3 and Step 3.5 Flash share?

18 benchmarks have published results for both models. Grok 4.3 has 40 scored results on Noometry and Step 3.5 Flash has 19.