# Grok 4 Fast vs Muse Glimmer

> Muse Glimmer is the stronger model overall, scoring 41.7 to 39.4 on the Noometry Index.

- Canonical page: https://noometry.com/compare/grok-4-fast-vs-muse-glimmer
- Last updated: 2026-10-10
- Shared benchmarks: 13

## Summary

- They share 13 benchmarks with published results for both. Grok 4 Fast scores higher in 5 categories and Muse Glimmer in 3 categories; 5 gaps are clear of the uncertainty.
- The widest gap is in long context, where Grok 4 Fast leads 63.2 to 42.1.
- Muse Glimmer has downloadable open weights; the other is API-only.

## Snapshot

| | Grok 4 Fast | Muse Glimmer |
|---|---|---|
| Provider | xAI | Meta |
| Noometry Index | 39.4 | 41.7 |
| Rank | 167 | 131 |
| Context | — | — |
| Input $/M | — | — |
| Output $/M | — | — |
| Weights | Proprietary | Open |

## Coding

- Grok 4 Fast: 32.5 (#271)
- Muse Glimmer: 40.4 (#142)

| Benchmark | Grok 4 Fast | Muse Glimmer |
|---|---|---|
| LMArena WebDev | 1159 | 1355 |
| LMArena Coding | 1429 | 1416 |
| SciCode | — | 44.9% |
| WeirdML | 42.9% | — |

## Agentic & Tool Use

- Grok 4 Fast: 29.5 (#86)
- Muse Glimmer: —

| Benchmark | Grok 4 Fast | Muse Glimmer |
|---|---|---|
| τ²-bench Banking | 15.7% | — |
| Cybench | 30% | — |
| LMArena Search | 1171 | — |

## Reasoning

- Grok 4 Fast: 22.2 (#201)
- Muse Glimmer: 25.7 (#144)

| Benchmark | Grok 4 Fast | Muse Glimmer |
|---|---|---|
| LMArena Hard Prompts | 1412 | 1396 |
| ARC-AGI-2 | 5.3% | — |
| Kagi LLM Benchmark | 66.1% | — |
| ARC-AGI-1 | 48.5% | — |
| CritPt | — | 2.6% |
| DTBench | 82.7% | — |
| Epoch Capabilities Index | 144.2 | — |
| ForecastBench | 60.5 | — |

## Math

- Grok 4 Fast: 38.9 (#123)
- Muse Glimmer: 38.8 (#125)

| Benchmark | Grok 4 Fast | Muse Glimmer |
|---|---|---|
| LMArena Math | 1419 | 1417 |

## Knowledge

- Grok 4 Fast: 32.0 (#214)
- Muse Glimmer: 38.5 (#143)

| Benchmark | Grok 4 Fast | Muse Glimmer |
|---|---|---|
| LMArena Expert | 1411 | 1386 |
| Vectara Hallucination Rate | 19.7% | — |

## Multilingual

- Grok 4 Fast: 51.3 (#111)
- Muse Glimmer: 50.5 (#122)

| Benchmark | Grok 4 Fast | Muse Glimmer |
|---|---|---|
| LMArena Non-English | 1396 | 1384 |
| LMArena Chinese | 1457 | 1412 |
| LMArena Russian | 1389 | 1390 |
| LMArena French | 1431 | — |
| LMArena German | 1383 | — |
| LMArena Japanese | 1352 | — |
| LMArena Korean | 1357 | — |
| LMArena Spanish | 1415 | — |

## Instruction Following

- Grok 4 Fast: 73.2 (#121)
- Muse Glimmer: 72.6 (#135)

| Benchmark | Grok 4 Fast | Muse Glimmer |
|---|---|---|
| LMArena Instruction Following | 1387 | 1375 |

## Long Context

- Grok 4 Fast: 63.2 (#3)
- Muse Glimmer: 42.1 (#129)

| Benchmark | Grok 4 Fast | Muse Glimmer |
|---|---|---|
| LMArena Longer Query | 1415 | 1382 |
| Fiction.LiveBench | 94.4% | — |

## Writing & Preference

- Grok 4 Fast: 60.0 (#102)
- Muse Glimmer: 57.5 (#126)

| Benchmark | Grok 4 Fast | Muse Glimmer |
|---|---|---|
| LMArena Text | 1407 | 1389 |
| LMArena Creative Writing | 1387 | 1339 |
| LMArena Multi-Turn | 1414 | 1399 |

## FAQ

### Is Grok 4 Fast better than Muse Glimmer?

Muse Glimmer is the stronger model overall, scoring 41.7 to 39.4 on the Noometry Index.

### Is Grok 4 Fast or Muse Glimmer better for coding?

Muse Glimmer scores higher on coding benchmarks: 40.4 versus 32.5 in the Noometry coding category.

### How many benchmarks do Grok 4 Fast and Muse Glimmer share?

13 benchmarks have published results for both models. Grok 4 Fast has 30 scored results on Noometry and Muse Glimmer has 15.