Grok 4.20 vs Muse Spark 1.2
Muse Spark 1.2 leads Grok 4.20 on coding, 55.7 to 33.3 on the Vibe Coding Index, and Grok 4.20 costs 1.7x less per output token ($2.50 vs $4.25 per million). Updated October 22, 2026; 39 benchmarks have a result for both.
Grok 4.20 or Muse Spark 1.2: which to pick
Pick Muse Spark 1.2 for coding: it scores 55.7 on the Vibe Coding Index against 33.3 for Grok 4.20.
Pick Grok 4.20 for output tokens 1.7x cheaper ($2.50 vs $4.25 per million) and a larger context window (2M against 1.05M tokens).
- Shared results
- 39
- Grok 4.20 only
- 16
- Muse Spark 1.2 only
- 58
- Like-for-like categories
- 7 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 Spark 1.2
Muse Spark 1.2 scores 55.7 against 33.3.
2 and 5 benchmarks behind the scores
Intelligence
AA Intelligence Index
Muse Spark 1.2
Muse Spark 1.2 leads, 39.6 against 25.7.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Muse Spark 1.2 has a AA Agentic Index result, 43.2.
Directional only
Reasoning
GPQA Diamond
No call
Only Grok 4.20 has a GPQA Diamond result, 88.6%.
Directional only
Math
AIME
No call
Only Grok 4.20 has a AIME result, 96.5%.
Directional only
Knowledge
MMLU Pro
Muse Spark 1.2
Muse Spark 1.2 leads, 88.3% against 86.3%.
Same board, both measured
Web design
Design Arena: websites
Muse Spark 1.2
Muse Spark 1.2 leads, 1312 against 1229.
Same board, both measured
Long documents
Listed context window
Grok 4.20
Grok 4.20 takes 2M tokens against 1.05M.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Grok 4.20
Grok 4.20 $0.0025, Muse Spark 1.2 $0.0034 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
Muse Spark 1.2
Grok 4.20 $0.72, Muse Spark 1.2 $0.64.
Published attempt cost and pass rate
At a glance
- Coding index
- Grok 4.20 33.3 from 2 benchmarks, Muse Spark 1.2 55.7 from 5 benchmarks.
- Widest category
- Coding, 30.5 points apart on average over 5 shared benchmarks.
- Widest single gap
- Vibe Code Bench (Vals AI): Grok 4.20 4.1% against Muse Spark 1.2 79.1%, 75.0 points apart on a 0 to 100 scale.
- Output price
- Grok 4.20 $2.50 against Muse Spark 1.2 $4.25 per million output tokens, 1.7x apart.
- Context window
- Grok 4.20 takes 2M tokens, Muse Spark 1.2 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 4.20 | Bars | Muse Spark 1.2 | Ties |
|---|---|---|---|---|
| Coding | 0 | 5 | ||
| Intelligence | 0 | 2 | ||
| Agentic work | 1 | 8 | ||
| Reasoning | 1 | 2 | ||
| Knowledge | 0 | 6 | ||
| Web design | 0 | 8 | ||
| General | 0 | 6 | ||
| All shared boards | 2 | 37 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index05
| Benchmark | Grok 4.20 | Muse Spark 1.2 | Leader |
|---|---|---|---|
| LiveBench coding | Not measured | 78.2% | Only Muse Spark 1.2 measured |
| LMArena WebDev | Not measured | 1534 | Only Muse Spark 1.2 measured |
| AA Coding Index | Not measured | 72.2 | Only Muse Spark 1.2 measured |
| LiveCodeBench (Vals AI) | 84.3% | Not measured | Only Grok 4.20 measured |
| SWE-bench Verified (Vals AI) | 72.2% | 86.6% | Muse Spark 1.2 |
| Terminal-Bench 4 (Vals AI) | Not measured | 6.1% | Only Muse Spark 1.2 measured |
| Vibe Code Bench (Vals AI) | 4.1% | 79.1% | Muse Spark 1.2 |
| Code migration (Vals AI) | 0.3% | 29.9% | Muse Spark 1.2 |
| ProgramBench (Vals AI) | Not measured | 0.5% | Only Muse Spark 1.2 measured |
| IOI (Vals AI) | Not measured | 21.8% | Only Muse Spark 1.2 measured |
| Terminal-Bench 2.1 (Vals AI) | 44.2% | 69.7% | Muse Spark 1.2 |
| SkillsBench (Vals AI) | Not measured | 53.0% | Only Muse Spark 1.2 measured |
| CyberBench (Vals AI) | Not measured | 69.5% | Only Muse Spark 1.2 measured |
| SciCode | Not measured | 57.4% | Only Muse Spark 1.2 measured |
| Terminal-Bench Hard (Artificial Analysis run) | 37.9% | Not measured | Only Grok 4.20 measured |
| Terminal-Bench | 57.3% | Not measured | Only Grok 4.20 measured |
| FrontierSWE | Not measured | 12.0% | Only Muse Spark 1.2 measured |
| WeirdML | 52.3% | 60.3% | Muse Spark 1.2 |
| LMArena Text: coding | Not measured | 1505 | Only Muse Spark 1.2 measured |
| LMArena Text: software and IT | Not measured | 1505 | Only Muse Spark 1.2 measured |
| LMArena WebDev: React | Not measured | 1526 | Only Muse Spark 1.2 measured |
| LMArena WebDev: HTML | Not measured | 1543 | Only Muse Spark 1.2 measured |
| Neither model has a result on the other 17 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | Grok 4.20 | Muse Spark 1.2 | Leader |
|---|---|---|---|
| AA Intelligence Index | 25.7 | 39.6 | Muse Spark 1.2 |
| Epoch Capabilities Index | 152.1 | 155.1 | Muse Spark 1.2 |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index18
| Benchmark | Grok 4.20 | Muse Spark 1.2 | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 43.2 | Only Muse Spark 1.2 measured |
| Design Arena: agents building web apps | 1144 | 1221 | Muse Spark 1.2 |
| Design Arena: agents building full-stack apps | 1054 | 1210 | Muse Spark 1.2 |
| Design Arena: agents building mobile apps | 1090 | 1181 | Muse Spark 1.2 |
| Design Arena: agents building Android apps | 1045 | 1222 | Muse Spark 1.2 |
| Design Arena: agents building Godot games | 1089 | Not measured | Only Grok 4.20 measured |
| Design Arena: agents building games | Not measured | 1179 | Only Muse Spark 1.2 measured |
| Design Arena: HTML slides | 1180 | 1085 | Grok 4.20 |
| Design Arena: PowerPoint slides | Not measured | 1172 | Only Muse Spark 1.2 measured |
| LiveBench research | Not measured | 67.7% | Only Muse Spark 1.2 measured |
| LiveBench browser | Not measured | 36.0% | Only Muse Spark 1.2 measured |
| LiveBench long agentic | Not measured | 21.3% | Only Muse Spark 1.2 measured |
| SREBench (Vals AI) | Not measured | 0.0% | Only Muse Spark 1.2 measured |
| Finance Agent (Vals AI) | 28.5% | 60.6% | Muse Spark 1.2 |
| Tax Agent Bench (Vals AI) | 7.0% | 32.8% | Muse Spark 1.2 |
| Legal Research Bench (Vals AI) | 13.9% | 43.8% | Muse Spark 1.2 |
| Excel Modeling Benchmark (Vals AI) | 11.7% | 57.0% | Muse Spark 1.2 |
| BioMysteryBench (Vals AI) | Not measured | 64.8% | Only Muse Spark 1.2 measured |
| τ²-Bench Telecom | 93.0% | Not measured | Only Grok 4.20 measured |
| APEX-Agents | Not measured | 45.4% | Only Muse Spark 1.2 measured |
| Vending-Bench 2 | $4,663 | Not measured | Only Grok 4.20 measured |
| Neither model has a result on the other 20 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index12
| Benchmark | Grok 4.20 | Muse Spark 1.2 | Leader |
|---|---|---|---|
| GPQA Diamond | 88.6% | Not measured | Only Grok 4.20 measured |
| LiveBench reasoning | Not measured | 90.0% | Only Muse Spark 1.2 measured |
| MMMU Pro (Vals AI) | 83.5% | 86.1% | Muse Spark 1.2 |
| GPQA Diamond (Artificial Analysis run) | 91.1% | 90.4% | Grok 4.20 |
| Humanity's Last Exam (Artificial Analysis run) | 34.5% | 45.5% | Muse Spark 1.2 |
| ARC-AGI | 89.5% | Not measured | Only Grok 4.20 measured |
| ARC-AGI-2 | 65.1% | Not measured | Only Grok 4.20 measured |
| SimpleBench | Not measured | 74.5% | Only Muse Spark 1.2 measured |
| Chess puzzles | Not measured | 27.0% | Only Muse Spark 1.2 measured |
| LMArena Text: hard prompts | Not measured | 1489 | Only Muse Spark 1.2 measured |
| LMArena Text: expert | Not measured | 1475 | Only Muse Spark 1.2 measured |
| LMArena Text: hard prompts in English | Not measured | 1487 | Only Muse Spark 1.2 measured |
| LMArena Vision: diagrams | Not measured | 1317 | Only Muse Spark 1.2 measured |
| Kagi LLM Benchmark | 75.0% | Not measured | Only Grok 4.20 measured |
| Neither model has a result on the other 8 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index4 boards, none shared
| Benchmark | Grok 4.20 | Muse Spark 1.2 | Leader |
|---|---|---|---|
| AIME | 96.5% | Not measured | Only Grok 4.20 measured |
| ProofBench | Not measured | 43.0% | Only Muse Spark 1.2 measured |
| LMArena Text: math | Not measured | 1484 | Only Muse Spark 1.2 measured |
| LMArena Text: mathematical work | Not measured | 1480 | Only Muse Spark 1.2 measured |
| Neither model has a result on the other 9 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index06
| Benchmark | Grok 4.20 | Muse Spark 1.2 | Leader |
|---|---|---|---|
| MMLU Pro | 86.3% | 88.3% | Muse Spark 1.2 |
| LegalBench (Vals AI) | 77.7% | 85.3% | Muse Spark 1.2 |
| CaseLaw (Vals AI) | 54.4% | Not measured | Only Grok 4.20 measured |
| CorpFin (Vals AI) | 63.7% | 70.9% | Muse Spark 1.2 |
| TaxEval (Vals AI) | 74.1% | 80.4% | Muse Spark 1.2 |
| MortgageTax (Vals AI) | 45.4% | 65.4% | Muse Spark 1.2 |
| MedQA (Vals AI) | 94.5% | Not measured | Only Grok 4.20 measured |
| MedCode (Vals AI) | 32.2% | 49.4% | Muse Spark 1.2 |
| SimpleQA Verified | Not measured | 60.3% | Only Muse Spark 1.2 measured |
| LMArena Text: science | Not measured | 1500 | Only Muse Spark 1.2 measured |
| LMArena Text: medicine and healthcare | Not measured | 1496 | Only Muse Spark 1.2 measured |
| LMArena Text: legal and government | Not measured | 1517 | Only Muse Spark 1.2 measured |
| LMArena Text: business and finance | Not measured | 1484 | Only Muse Spark 1.2 measured |
| Neither model has a result on the other 5 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index08
| Benchmark | Grok 4.20 | Muse Spark 1.2 | Leader |
|---|---|---|---|
| Design Arena: websites | 1229 | 1312 | Muse Spark 1.2 |
| Design Arena: UI components | 1200 | 1298 | Muse Spark 1.2 |
| Design Arena: game dev | 1193 | 1301 | Muse Spark 1.2 |
| Design Arena: data viz | 1217 | 1334 | Muse Spark 1.2 |
| Design Arena: 3D | 1193 | 1301 | Muse Spark 1.2 |
| Design Arena: all code categories | 1221 | 1312 | Muse Spark 1.2 |
| Design Arena: SVG | 1165 | 1284 | Muse Spark 1.2 |
| Design Arena: ASCII art | 1175 | 1284 | Muse Spark 1.2 |
| LiveBench design | Not measured | 67.1% | Only Muse Spark 1.2 measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index06
| Benchmark | Grok 4.20 | Muse Spark 1.2 | Leader |
|---|---|---|---|
| LiveBench data analysis | Not measured | 76.5% | Only Muse Spark 1.2 measured |
| Public Benefits Bench (Vals AI) | Not measured | 68.5% | Only Muse Spark 1.2 measured |
| SAGE (Vals AI) | 38.2% | 47.7% | Muse Spark 1.2 |
| MedScribe (Vals AI) | 63.4% | 90.1% | Muse Spark 1.2 |
| Vals Multimodal Index | 39.1% | 69.8% | Muse Spark 1.2 |
| IFBench | 81.2% | Not measured | Only Grok 4.20 measured |
| Long context reasoning (AA-LCR) | 69.0% | 79.0% | Muse Spark 1.2 |
| DTBench | 90.1% | 94.7% | Muse Spark 1.2 |
| LMCA | 38.7% | 48.4% | Muse Spark 1.2 |
| CL-bench | 22.2% | Not measured | Only Grok 4.20 measured |
| CL-bench Life | 11.9% | Not measured | Only Grok 4.20 measured |
| LMArena Text | Not measured | 1482 | Only Muse Spark 1.2 measured |
| LMArena Text: instruction following | Not measured | 1462 | Only Muse Spark 1.2 measured |
| LMArena Text: creative writing | Not measured | 1436 | Only Muse Spark 1.2 measured |
| LMArena Vision | Not measured | 1304 | Only Muse Spark 1.2 measured |
| LMArena Text: English | Not measured | 1483 | Only Muse Spark 1.2 measured |
| LMArena Text: non-English | Not measured | 1476 | Only Muse Spark 1.2 measured |
| LMArena Text: Chinese | Not measured | 1509 | Only Muse Spark 1.2 measured |
| LMArena Text: Korean | Not measured | 1462 | Only Muse Spark 1.2 measured |
| LMArena Text: French | Not measured | 1495 | Only Muse Spark 1.2 measured |
| LMArena Text: Spanish | Not measured | 1484 | Only Muse Spark 1.2 measured |
| LMArena Text: Russian | Not measured | 1483 | Only Muse Spark 1.2 measured |
| LMArena Text: multi-turn | Not measured | 1502 | Only Muse Spark 1.2 measured |
| LMArena Text: longer queries | Not measured | 1473 | Only Muse Spark 1.2 measured |
| LMArena Text: writing and language | Not measured | 1453 | Only Muse Spark 1.2 measured |
| LMArena Text: entertainment and media | Not measured | 1443 | Only Muse Spark 1.2 measured |
| LMArena Vision: English | Not measured | 1291 | Only Muse Spark 1.2 measured |
| LMArena Vision: reading text | Not measured | 1313 | Only Muse Spark 1.2 measured |
| Neither model has a result on the other 18 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Grok 4.20 | Muse Spark 1.2 | 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 4.20 costs less
Repository review
50K input + 3K output tokens
Grok 4.20 costs less
Agent loop
200K input + 10K output tokens
Grok 4.20 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 4.20 | Meta Muse Spark 1.2 |
|---|---|---|
| Maker | xAI | Meta |
| Weights | No public weights listed | No public weights listed |
| Released | March 31, 2026 | August 5, 2026 |
| Context window | 2M | 1.05M |
| Input $/Mtok | $1.25 | $1.25 |
| Output $/Mtok | $2.50 | $4.25 |
| Coding index | 33.3 | 55.7 |
| Independent measurements behind it | 2 | 5 |
| Cost per solved task | $0.72 | $0.64 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Grok 4.20 better than Muse Spark 1.2 for coding?
Pick Muse Spark 1.2 for coding: it scores 55.7 on the Vibe Coding Index against 33.3 for Grok 4.20. Pick Grok 4.20 for output tokens 1.7x cheaper ($2.50 vs $4.25 per million) and a larger context window (2M against 1.05M tokens).
Which is cheaper, Grok 4.20 or Muse Spark 1.2?
Grok 4.20 costs $1.25 per million input tokens and $2.50 per million output tokens; Muse Spark 1.2 costs $1.25 and $4.25. Per solved SWE-bench Verified task, Grok 4.20 costs $0.72 and Muse Spark 1.2 $0.64.
Which has the bigger context window, Grok 4.20 or Muse Spark 1.2?
Grok 4.20, with 2M tokens against 1.05M.
How many benchmarks is the Grok 4.20 vs Muse Spark 1.2 comparison based on?
39 benchmarks have a result for both models as of October 22, 2026. Grok 4.20's coding index rests on 2 independent benchmarks and Muse Spark 1.2's on 5. Where only one model has a result, the page says so instead of naming a winner.