Grok 4.5 vs Muse Ember
Muse Ember leads Grok 4.5 on coding, 64.9 to 52.3 on the Vibe Coding Index, and Muse Ember costs 12.0x less per output token ($0.50 vs $6.00 per million). Updated November 14, 2026; 9 benchmarks have a result for both.
vs boards won of 9 shared
Grok 4.5 or Muse Ember: which to pick
Pick Muse Ember for coding: it scores 64.9 on the Vibe Coding Index against 52.3 for Grok 4.5, though on 3 benchmarks against 5.
Grok 4.5 is neither cheaper nor larger in context, and leads no benchmark both models were measured on.
Model AGrok 4.5xAI52.3/1005 independent benchmarks$0.62 per solved taskModel BMuse EmberMeta64.9/1003 independent benchmarksNo cost per solved task
- Shared results
- 9
- Grok 4.5 only
- 114
- Muse Ember only
- 6
- Like-for-like categories
- 2 of 9
Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, six public coding benchmarks
Muse Ember
Muse Ember scores 64.9 against 52.3.
5 and 3 benchmarks behind the scores
Agentic work
AA Agentic Index
No call
Only Grok 4.5 has a AA Agentic Index result, 41.2.
Directional only
Reasoning
GPQA Diamond
No call
Only Grok 4.5 has a GPQA Diamond result, 92.9%.
Directional only
Knowledge
MMLU Pro
No call
Only Grok 4.5 has a MMLU Pro result, 89.2%.
Directional only
Web design
Design Arena: websites
No call
Only Grok 4.5 has a Design Arena: websites result, 1273.
Directional only
General
Vals Index
No call
Only Muse Ember has a Vals Index result, 60.5%.
Directional only
Long documents
Listed context window
Muse Ember
Muse Ember takes 1.05M tokens against 500K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Muse Ember
Grok 4.5 $0.0050, Muse Ember $0.0003 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Grok 4.5 has the number, $0.62.
Directional only
At a glance
- Coding index
- Grok 4.5 52.3 from 5 benchmarks, Muse Ember 64.9 from 3 benchmarks.
- Widest category
- Coding, 17.9 points apart on average over 6 shared benchmarks.
- Widest single gap
- Terminal-Bench 4 (Vals AI): Grok 4.5 8.6% against Muse Ember 39.4%, 41.1 points apart on a 0 to 100 scale.
- Output price
- Grok 4.5 $6.00 against Muse Ember $0.50 per million output tokens, 12.0x apart.
- Context window
- Grok 4.5 takes 500K tokens, Muse Ember 1.05M.
Benchmark by benchmark
First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.
| Category | Grok 4.5 | Bars | Muse Ember | Ties |
|---|---|---|---|---|
| Coding | 0 | 6 | ||
| Agentic work | 0 | 3 | ||
| All shared boards | 0 | 9 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index06
| Benchmark | Grok 4.5 | Muse Ember | Leader |
|---|---|---|---|
| LMArena WebDev | 1553 | 1609 | Muse Ember |
| AA Coding Index | 72.4 | Not measured | Only Grok 4.5 measured |
| LiveCodeBench (Vals AI) | 87.3% | Not measured | Only Grok 4.5 measured |
| SWE-bench Verified (Vals AI) | 86.6% | Not measured | Only Grok 4.5 measured |
| Terminal-Bench 4 (Vals AI) | 8.6% | 39.4% | Muse Ember |
| Vibe Code Bench (Vals AI) | 69.0% | 83.7% | Muse Ember |
| Code migration (Vals AI) | 36.6% | Not measured | Only Grok 4.5 measured |
| ProgramBench (Vals AI) | 0.0% | Not measured | Only Grok 4.5 measured |
| IOI (Vals AI) | 40.6% | Not measured | Only Grok 4.5 measured |
| Terminal-Bench 2.1 (Vals AI) | 67.8% | Not measured | Only Grok 4.5 measured |
| SkillsBench (Vals AI) | 66.0% | Not measured | Only Grok 4.5 measured |
| CyberBench (Vals AI) | 71.0% | Not measured | Only Grok 4.5 measured |
| SciCode | 55.0% | Not measured | Only Grok 4.5 measured |
| Terminal-Bench 4.0 (Artificial Analysis run) | 10.6% | 40.9% | Muse Ember |
| FrontierCode 2.0 | Not measured | 27.2% | Only Muse Ember measured |
| FrontierCode | 42.4% | Not measured | Only Grok 4.5 measured |
| WeirdML | 46.4% | Not measured | Only Grok 4.5 measured |
| MirrorCode | 32.2% | Not measured | Only Grok 4.5 measured |
| ALE-Bench | 1309.3 | Not measured | Only Grok 4.5 measured |
| LMArena Text: coding | 1474 | Not measured | Only Grok 4.5 measured |
| LMArena Text: software and IT | 1471 | Not measured | Only Grok 4.5 measured |
| LMArena WebDev: React | 1556 | 1616 | Muse Ember |
| LMArena WebDev: HTML | 1565 | 1621 | Muse Ember |
| LMArena WebDev: from an image | 1562 | Not measured | Only Grok 4.5 measured |
| SciCode | 6.5% | Not measured | Only Grok 4.5 measured |
| GameBench 2 | 61.5 | Not measured | Only Grok 4.5 measured |
| Terminal-Bench 2.1 | 79.3% | Not measured | Only Grok 4.5 measured |
| Terminal-Bench 3.0 | 15.7% | Not measured | Only Grok 4.5 measured |
| Terminal-Bench 4.0 | 12.4% | Not measured | Only Grok 4.5 measured |
| Neither model has a result on the other 23 boards here | |||
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index1 board, none shared
| Benchmark | Grok 4.5 | Muse Ember | Leader |
|---|---|---|---|
| Epoch Capabilities Index | 155.0 | Not measured | Only Grok 4.5 measured |
| Neither model has a result on the other 1 board here | |||
Agentic workLike-for-likePublic boards, shown as published, kept out of the index03
| Benchmark | Grok 4.5 | Muse Ember | Leader |
|---|---|---|---|
| AA Agentic Index | 41.2 | Not measured | Only Grok 4.5 measured |
| Design Arena: agents building web apps | 1196 | Not measured | Only Grok 4.5 measured |
| Design Arena: agents building full-stack apps | 1223 | Not measured | Only Grok 4.5 measured |
| Design Arena: agents building mobile apps | 1206 | Not measured | Only Grok 4.5 measured |
| Design Arena: agents building Android apps | 1227 | Not measured | Only Grok 4.5 measured |
| Design Arena: agents building Godot games | 1206 | Not measured | Only Grok 4.5 measured |
| Design Arena: agents building games | 1184 | Not measured | Only Grok 4.5 measured |
| Design Arena: HTML slides | 1099 | Not measured | Only Grok 4.5 measured |
| Design Arena: PowerPoint slides | 1197 | Not measured | Only Grok 4.5 measured |
| Design Arena: spreadsheets | 1041 | Not measured | Only Grok 4.5 measured |
| SREBench (Vals AI) | 0.8% | Not measured | Only Grok 4.5 measured |
| Finance Agent (Vals AI) | 48.4% | Not measured | Only Grok 4.5 measured |
| Tax Agent Bench (Vals AI) | 24.9% | 38.2% | Muse Ember |
| Legal Research Bench (Vals AI) | 38.0% | 49.0% | Muse Ember |
| Harvey's Legal Agent Benchmark (Vals AI) | Not measured | 25.0% | Only Muse Ember measured |
| Excel Modeling Benchmark (Vals AI) | 52.9% | Not measured | Only Grok 4.5 measured |
| Time Horizon Index (Vals AI) | 6.3% | Not measured | Only Grok 4.5 measured |
| APEX-Agents | 56.2% | 64.3% | Muse Ember |
| PostTrainBench | 22.6% | Not measured | Only Grok 4.5 measured |
| Vending-Bench 2 | $3,887 | Not measured | Only Grok 4.5 measured |
| LMArena Search | 1216 | Not measured | Only Grok 4.5 measured |
| τ³-Banking | 47.9% | Not measured | Only Grok 4.5 measured |
| Neither model has a result on the other 22 boards here | |||
ReasoningDirectional onlyPublic boards, shown as published, kept out of the index17 boards, none shared
| Benchmark | Grok 4.5 | Muse Ember | Leader |
|---|---|---|---|
| GPQA Diamond | 92.9% | Not measured | Only Grok 4.5 measured |
| MMMU Pro (Vals AI) | 61.8% | Not measured | Only Grok 4.5 measured |
| GPQA Diamond (Artificial Analysis run) | 93.1% | Not measured | Only Grok 4.5 measured |
| Humanity's Last Exam (Artificial Analysis run) | 42.7% | Not measured | Only Grok 4.5 measured |
| HLE-Diamond (Artificial Analysis run) | Not measured | 25.1% | Only Muse Ember measured |
| CritPt v2, hard subset (Artificial Analysis run) | Not measured | 39.0% | Only Muse Ember measured |
| GPQA Diamond (Epoch AI run) | 93.4% | Not measured | Only Grok 4.5 measured |
| ARC-AGI | 87.2% | Not measured | Only Grok 4.5 measured |
| ARC-AGI-2 | 52.6% | Not measured | Only Grok 4.5 measured |
| SimpleBench | 70.0% | Not measured | Only Grok 4.5 measured |
| Chess puzzles | 35.0% | Not measured | Only Grok 4.5 measured |
| LMArena Text: hard prompts | 1462 | Not measured | Only Grok 4.5 measured |
| LMArena Text: expert | 1466 | Not measured | Only Grok 4.5 measured |
| LMArena Text: hard prompts in English | 1464 | Not measured | Only Grok 4.5 measured |
| LMArena Vision: diagrams | 1304 | Not measured | Only Grok 4.5 measured |
| LMArena Vision: homework | 1301 | Not measured | Only Grok 4.5 measured |
| Kagi LLM Benchmark | 83.5% | Not measured | Only Grok 4.5 measured |
| Neither model has a result on the other 9 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index7 boards, none shared
| Benchmark | Grok 4.5 | Muse Ember | Leader |
|---|---|---|---|
| OTIS Mock AIME | 97.8% | Not measured | Only Grok 4.5 measured |
| FrontierMath, tiers 1 to 3 | 57.2% | Not measured | Only Grok 4.5 measured |
| FrontierMath, tier 4 | 24.4% | Not measured | Only Grok 4.5 measured |
| ProofBench | 31.0% | Not measured | Only Grok 4.5 measured |
| LMArena Text: math | 1457 | Not measured | Only Grok 4.5 measured |
| LMArena Text: mathematical work | 1479 | Not measured | Only Grok 4.5 measured |
| MathArena | 30.8% | Not measured | Only Grok 4.5 measured |
| Neither model has a result on the other 7 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index12 boards, none shared
| Benchmark | Grok 4.5 | Muse Ember | Leader |
|---|---|---|---|
| MMLU Pro | 89.2% | Not measured | Only Grok 4.5 measured |
| LegalBench (Vals AI) | 86.0% | Not measured | Only Grok 4.5 measured |
| CorpFin (Vals AI) | 67.4% | Not measured | Only Grok 4.5 measured |
| TaxEval (Vals AI) | 71.7% | Not measured | Only Grok 4.5 measured |
| MortgageTax (Vals AI) | 61.8% | Not measured | Only Grok 4.5 measured |
| MedCode (Vals AI) | 43.3% | Not measured | Only Grok 4.5 measured |
| AA-Omniscience | Not measured | 7.7 | Only Muse Ember measured |
| SimpleQA Verified | 48.3% | Not measured | Only Grok 4.5 measured |
| LMArena Text: science | 1464 | Not measured | Only Grok 4.5 measured |
| LMArena Text: medicine and healthcare | 1438 | Not measured | Only Grok 4.5 measured |
| LMArena Text: legal and government | 1464 | Not measured | Only Grok 4.5 measured |
| LMArena Text: business and finance | 1441 | Not measured | Only Grok 4.5 measured |
| Neither model has a result on the other 9 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index8 boards, none shared
| Benchmark | Grok 4.5 | Muse Ember | Leader |
|---|---|---|---|
| Design Arena: websites | 1273 | Not measured | Only Grok 4.5 measured |
| Design Arena: UI components | 1269 | Not measured | Only Grok 4.5 measured |
| Design Arena: game dev | 1250 | Not measured | Only Grok 4.5 measured |
| Design Arena: data viz | 1264 | Not measured | Only Grok 4.5 measured |
| Design Arena: 3D | 1234 | Not measured | Only Grok 4.5 measured |
| Design Arena: all code categories | 1264 | Not measured | Only Grok 4.5 measured |
| Design Arena: SVG | 1200 | Not measured | Only Grok 4.5 measured |
| Design Arena: ASCII art | 1249 | Not measured | Only Grok 4.5 measured |
| Neither model has a result on the other 1 board here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index33 boards, none shared
| Benchmark | Grok 4.5 | Muse Ember | Leader |
|---|---|---|---|
| Vals Index | Not measured | 60.5% | Only Muse Ember measured |
| MedScribe (Vals AI) | 86.9% | Not measured | Only Grok 4.5 measured |
| Vals Multimodal Index | 63.4% | Not measured | Only Grok 4.5 measured |
| Long context reasoning (AA-LCR) | 79.3% | Not measured | Only Grok 4.5 measured |
| GDPval-AA | 1388 | Not measured | Only Grok 4.5 measured |
| DTBench | 96.5% | Not measured | Only Grok 4.5 measured |
| LMCA | 45.2% | Not measured | Only Grok 4.5 measured |
| Surface Evolver Bench | 74.4% | Not measured | Only Grok 4.5 measured |
| Furniture assembly | 22.5% | Not measured | Only Grok 4.5 measured |
| LMArena Text | 1448 | Not measured | Only Grok 4.5 measured |
| LMArena Text: instruction following | 1446 | Not measured | Only Grok 4.5 measured |
| LMArena Text: creative writing | 1442 | Not measured | Only Grok 4.5 measured |
| LMArena Vision | 1288 | Not measured | Only Grok 4.5 measured |
| LMArena Text: English | 1453 | Not measured | Only Grok 4.5 measured |
| LMArena Text: non-English | 1440 | Not measured | Only Grok 4.5 measured |
| LMArena Text: Chinese | 1496 | Not measured | Only Grok 4.5 measured |
| LMArena Text: German | 1448 | Not measured | Only Grok 4.5 measured |
| LMArena Text: Japanese | 1433 | Not measured | Only Grok 4.5 measured |
| LMArena Text: Korean | 1409 | Not measured | Only Grok 4.5 measured |
| LMArena Text: French | 1455 | Not measured | Only Grok 4.5 measured |
| LMArena Text: Spanish | 1452 | Not measured | Only Grok 4.5 measured |
| LMArena Text: Russian | 1450 | Not measured | Only Grok 4.5 measured |
| LMArena Text: Polish | 1431 | Not measured | Only Grok 4.5 measured |
| LMArena Text: multi-turn | 1455 | Not measured | Only Grok 4.5 measured |
| LMArena Text: longer queries | 1463 | Not measured | Only Grok 4.5 measured |
| LMArena Text: writing and language | 1445 | Not measured | Only Grok 4.5 measured |
| LMArena Text: entertainment and media | 1434 | Not measured | Only Grok 4.5 measured |
| LMArena Vision: English | 1284 | Not measured | Only Grok 4.5 measured |
| LMArena Vision: Chinese | 1339 | Not measured | Only Grok 4.5 measured |
| LMArena Vision: reading text | 1293 | Not measured | Only Grok 4.5 measured |
| LMArena Vision: humor | 1276 | Not measured | Only Grok 4.5 measured |
| LMArena Vision: creative writing | 1291 | Not measured | Only Grok 4.5 measured |
| LMArena Document | 1451 | Not measured | Only Grok 4.5 measured |
| Neither model has a result on the other 16 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Grok 4.5 | Muse Ember | Leader |
|---|---|---|---|
| Neither model has a result on 5 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
Grok 4.5$0.0050Fits in one request
Muse Ember$0.0003Fits in one request
Muse Ember costs less
Repository review
50K input + 3K output tokens
Grok 4.5$0.118Fits in one request
Muse Ember$0.0065Fits in one request
Muse Ember costs less
Agent loop
200K input + 10K output tokens
Grok 4.5$0.460Fits in one request
Muse Ember$0.025Fits in one request
Muse Ember costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | SpaceXAI Grok 4.5 | Meta Muse Ember |
|---|---|---|
| Maker | xAI | Meta |
| Weights | No public weights listed | No public weights listed |
| Released | July 8, 2026 | November 9, 2026 |
| Context window | 500K | 1.05M |
| Input $/Mtok | $2.00 | $0.10 |
| Output $/Mtok | $6.00 | $0.50 |
| Coding index | 52.3 | 64.9 |
| Independent measurements behind it | 5 | 3 |
| Cost per solved task | $0.62 | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Grok 4.5 better than Muse Ember for coding?
Pick Muse Ember for coding: it scores 64.9 on the Vibe Coding Index against 52.3 for Grok 4.5, though on 3 benchmarks against 5. Grok 4.5 is neither cheaper nor larger in context, and leads no benchmark both models were measured on.
Which is cheaper, Grok 4.5 or Muse Ember?
Grok 4.5 costs $2.00 per million input tokens and $6.00 per million output tokens; Muse Ember costs $0.10 and $0.50. Cost per solved task is known for Grok 4.5 only.
Which has the bigger context window, Grok 4.5 or Muse Ember?
Muse Ember, with 1.05M tokens against 500K.
How many benchmarks is the Grok 4.5 vs Muse Ember comparison based on?
9 benchmarks have a result for both models as of November 14, 2026. Grok 4.5's coding index rests on 5 independent benchmarks and Muse Ember's on 3. Where only one model has a result, the page says so instead of naming a winner.