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GPT-5.5 vs Muse Spark 1.2

Updated October 21, 2026. 92 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace GPT-5.5 Replace Muse Spark 1.2
GPT-5.5OpenAI
Coding
67.8
Overall
38.4
Output $/M
$30.00
38
Muse Spark 1.2Meta
Coding
65.1
Overall
39.6
Output $/M
$4.25
52
vs boards won of 92 shared, 2 tied

Decision reading

Pick GPT-5.5 for coding: it scores 67.8 on the Vibe Coding Index against 65.1 for Muse Spark 1.2.

Pick Muse Spark 1.2 when output tokens cost 7.1x less, or when a solved task costs $0.64 against $1.65.

Model AGPT-5.5OpenAI67.8/1002 independent benchmarks$1.65 per solved taskModel BMuse Spark 1.2Meta65.1/1002 independent benchmarks$0.64 per solved task
Shared results
92
GPT-5.5 only
40
Muse Spark 1.2 only
5
Like-for-like categories
8 of 9

Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.

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.

At a glance

Coding index
GPT-5.5 67.8 from 2 benchmarks, Muse Spark 1.2 65.1 from 2 benchmarks.
Widest category
Agentic work, 9.0 points apart on average over 17 shared benchmarks.
Widest single gap
Chess puzzles: GPT-5.5 63.0% against Muse Spark 1.2 27.0%, 36.0 points apart on a 0 to 100 scale.
Output price
GPT-5.5 $30.00 against Muse Spark 1.2 $4.25 per million output tokens, 7.1x apart.
Context window
GPT-5.5 takes 1.05M 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.

Boards won, where both have a result
CategoryGPT-5.5BarsMuse Spark 1.2Ties
Coding771 tie
Intelligence11
Agentic work5111 tie
Reasoning64
Math30
Knowledge38
Web design18
General1213
All shared boards38522 ties
CodingLike-for-likeFour of these boards feed the Vibe Coding Index77
Coding benchmarks for GPT-5.5 and Muse Spark 1.2
BenchmarkGPT-5.5Muse Spark 1.2Leader
LiveBench coding85.1%78.2%GPT-5.5
LMArena WebDev15131534Muse Spark 1.2
AA Coding Index74.972.2GPT-5.5
LiveCodeBench (Vals AI)85.3%Not measuredOnly GPT-5.5 measured
SWE-bench Verified (Vals AI)82.6%86.6%Muse Spark 1.2
Terminal-Bench 4 (Vals AI)Not measured6.1%Only Muse Spark 1.2 measured
Vibe Code Bench (Vals AI)69.8%79.1%Muse Spark 1.2
Code migration (Vals AI)45.2%29.9%GPT-5.5
ProgramBench (Vals AI)0.5%0.5%Tie
IOI (Vals AI)Not measured21.8%Only Muse Spark 1.2 measured
Terminal-Bench 2.1 (Vals AI)76.4%69.7%GPT-5.5
SkillsBench (Vals AI)62.5%53.0%GPT-5.5
CyberBench (Vals AI)Not measured69.5%Only Muse Spark 1.2 measured
SciCode56.1%57.4%Muse Spark 1.2
Terminal-Bench Hard (Artificial Analysis run)60.6%Not measuredOnly GPT-5.5 measured
Terminal-Bench84.7%Not measuredOnly GPT-5.5 measured
FrontierCode43.0%Not measuredOnly GPT-5.5 measured
FrontierSWENot measured12.0%Only Muse Spark 1.2 measured
GSO-Bench40.2%Not measuredOnly GPT-5.5 measured
WeirdML84.9%60.3%GPT-5.5
MirrorCode10.0%Not measuredOnly GPT-5.5 measured
ALE-Bench1943.0Not measuredOnly GPT-5.5 measured
LMArena Text: coding14941505Muse Spark 1.2
LMArena Text: software and IT14931505Muse Spark 1.2
LMArena WebDev: React15061526Muse Spark 1.2
LMArena WebDev: HTML15431543GPT-5.5
LMArena WebDev: from an image1532Not measuredOnly GPT-5.5 measured
Neither model has a result on the other 11 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index11
Intelligence benchmarks for GPT-5.5 and Muse Spark 1.2
BenchmarkGPT-5.5Muse Spark 1.2Leader
AA Intelligence Index38.439.6Muse Spark 1.2
Epoch Capabilities Index159.7155.1GPT-5.5
Agentic workLike-for-likePublic boards, shown as published, kept out of the index511
Agentic work benchmarks for GPT-5.5 and Muse Spark 1.2
BenchmarkGPT-5.5Muse Spark 1.2Leader
AA Agentic Index36.443.2Muse Spark 1.2
Design Arena: agents building web apps11171222Muse Spark 1.2
Design Arena: agents building full-stack apps10891210Muse Spark 1.2
Design Arena: agents building mobile apps11431182Muse Spark 1.2
Design Arena: agents building Android apps11691228Muse Spark 1.2
Design Arena: agents building Godot games1173Not measuredOnly GPT-5.5 measured
Design Arena: agents building games11791179Tie
Design Arena: HTML slides10671135Muse Spark 1.2
Design Arena: PowerPoint slides11081198Muse Spark 1.2
LiveBench research61.6%67.7%Muse Spark 1.2
LiveBench browser48.0%36.0%GPT-5.5
LiveBench long agentic44.6%21.3%GPT-5.5
SREBench (Vals AI)3.8%0.0%GPT-5.5
Finance Agent (Vals AI)51.8%60.6%Muse Spark 1.2
Tax Agent Bench (Vals AI)21.8%32.8%Muse Spark 1.2
Legal Research Bench (Vals AI)40.4%43.8%Muse Spark 1.2
Excel Modeling Benchmark (Vals AI)64.5%57.0%GPT-5.5
BioMysteryBench (Vals AI)Not measured64.8%Only Muse Spark 1.2 measured
Time Horizon Index (Vals AI)8.3%Not measuredOnly GPT-5.5 measured
τ²-Bench Telecom93.9%Not measuredOnly GPT-5.5 measured
APEX-Agents55.1%45.4%GPT-5.5
Remote Labor Index6.3%Not measuredOnly GPT-5.5 measured
OSWorld 2.013.0%Not measuredOnly GPT-5.5 measured
DeepResearch Bench54.0%Not measuredOnly GPT-5.5 measured
PostTrainBench27.2%Not measuredOnly GPT-5.5 measured
Vending-Bench 2$7,524Not measuredOnly GPT-5.5 measured
Neither model has a result on the other 13 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index64
Reasoning benchmarks for GPT-5.5 and Muse Spark 1.2
BenchmarkGPT-5.5Muse Spark 1.2Leader
GPQA Diamond93.2%Not measuredOnly GPT-5.5 measured
LiveBench reasoning89.7%90.0%Muse Spark 1.2
MMMU Pro (Vals AI)88.3%86.1%GPT-5.5
GPQA Diamond (Artificial Analysis run)93.5%90.4%GPT-5.5
Humanity's Last Exam (Artificial Analysis run)45.8%45.5%GPT-5.5
GPQA Diamond (Epoch AI run)90.7%Not measuredOnly GPT-5.5 measured
ARC-AGI95.0%Not measuredOnly GPT-5.5 measured
ARC-AGI-285.0%Not measuredOnly GPT-5.5 measured
SimpleBench69.0%74.5%Muse Spark 1.2
Chess puzzles63.0%27.0%GPT-5.5
Mystery game puzzles56.0%Not measuredOnly GPT-5.5 measured
EBR-bench34.3%Not measuredOnly GPT-5.5 measured
LMArena Text: hard prompts14891489Muse Spark 1.2
LMArena Text: expert15071475GPT-5.5
LMArena Text: hard prompts in English14831487Muse Spark 1.2
LMArena Vision: diagrams13251317GPT-5.5
LMArena Vision: homework1332Not measuredOnly GPT-5.5 measured
Neither model has a result on the other 4 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index30
Math benchmarks for GPT-5.5 and Muse Spark 1.2
BenchmarkGPT-5.5Muse Spark 1.2Leader
OTIS Mock AIME84.4%Not measuredOnly GPT-5.5 measured
FrontierMath, tiers 1 to 385.3%Not measuredOnly GPT-5.5 measured
FrontierMath, tier 472.5%Not measuredOnly GPT-5.5 measured
ProofBench50.0%43.0%GPT-5.5
LMArena Text: math14871484GPT-5.5
LMArena Text: mathematical work14961480GPT-5.5
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index38
Knowledge benchmarks for GPT-5.5 and Muse Spark 1.2
BenchmarkGPT-5.5Muse Spark 1.2Leader
MMLU Pro88.1%88.3%Muse Spark 1.2
LegalBench (Vals AI)86.5%85.3%GPT-5.5
CaseLaw (Vals AI)66.2%Not measuredOnly GPT-5.5 measured
CorpFin (Vals AI)68.4%70.9%Muse Spark 1.2
TaxEval (Vals AI)75.0%80.4%Muse Spark 1.2
MortgageTax (Vals AI)68.8%65.4%GPT-5.5
MedCode (Vals AI)49.1%49.4%Muse Spark 1.2
SimpleQA Verified63.0%60.3%GPT-5.5
LMArena Text: science14851500Muse Spark 1.2
LMArena Text: medicine and healthcare14651496Muse Spark 1.2
LMArena Text: legal and government14911517Muse Spark 1.2
LMArena Text: business and finance14781484Muse Spark 1.2
Neither model has a result on the other 5 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index18
Web design benchmarks for GPT-5.5 and Muse Spark 1.2
BenchmarkGPT-5.5Muse Spark 1.2Leader
Design Arena: websites12561313Muse Spark 1.2
Design Arena: UI components12601300Muse Spark 1.2
Design Arena: game dev12941302Muse Spark 1.2
Design Arena: data viz12651334Muse Spark 1.2
Design Arena: 3D11981301Muse Spark 1.2
Design Arena: all code categories12601313Muse Spark 1.2
Design Arena: SVG12341285Muse Spark 1.2
Design Arena: ASCII art12541284Muse Spark 1.2
LiveBench design70.3%67.1%GPT-5.5
GeneralLike-for-likePublic boards, shown as published, kept out of the index1213
General benchmarks for GPT-5.5 and Muse Spark 1.2
BenchmarkGPT-5.5Muse Spark 1.2Leader
LiveBench data analysis81.6%76.5%GPT-5.5
Public Benefits Bench (Vals AI)60.9%68.5%Muse Spark 1.2
SAGE (Vals AI)51.5%47.7%GPT-5.5
MedScribe (Vals AI)86.9%90.1%Muse Spark 1.2
Vals Multimodal Index68.1%69.8%Muse Spark 1.2
IFBench75.9%Not measuredOnly GPT-5.5 measured
Long context reasoning (AA-LCR)84.3%79.0%GPT-5.5
DTBench96.0%94.7%GPT-5.5
LMCA54.3%48.4%GPT-5.5
Surface Evolver Bench88.1%Not measuredOnly GPT-5.5 measured
Furniture assembly44.2%Not measuredOnly GPT-5.5 measured
ExploitBench47.4%Not measuredOnly GPT-5.5 measured
CL-bench Life22.2%Not measuredOnly GPT-5.5 measured
LMArena Text14711482Muse Spark 1.2
LMArena Text: instruction following14781462GPT-5.5
LMArena Text: creative writing14551436GPT-5.5
LMArena Vision12971304Muse Spark 1.2
LMArena Text: English14701483Muse Spark 1.2
LMArena Text: non-English14671476Muse Spark 1.2
LMArena Text: Chinese15341509GPT-5.5
LMArena Text: German1480Not measuredOnly GPT-5.5 measured
LMArena Text: Japanese1499Not measuredOnly GPT-5.5 measured
LMArena Text: Korean14601462Muse Spark 1.2
LMArena Text: French14851495Muse Spark 1.2
LMArena Text: Spanish14681484Muse Spark 1.2
LMArena Text: Russian14731483Muse Spark 1.2
LMArena Text: Polish1465Not measuredOnly GPT-5.5 measured
LMArena Text: multi-turn14761502Muse Spark 1.2
LMArena Text: longer queries14841473GPT-5.5
LMArena Text: writing and language14661453GPT-5.5
LMArena Text: entertainment and media14491443GPT-5.5
LMArena Vision: English12921291GPT-5.5
LMArena Vision: Chinese1360Not measuredOnly GPT-5.5 measured
LMArena Vision: reading text13061313Muse Spark 1.2
LMArena Vision: humor1293Not measuredOnly GPT-5.5 measured
LMArena Vision: recognizing things1231Not measuredOnly GPT-5.5 measured
LMArena Vision: creative writing1301Not measuredOnly GPT-5.5 measured
LMArena Document1486Not measuredOnly GPT-5.5 measured
Neither model has a result on the other 8 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for GPT-5.5 and Muse Spark 1.2
BenchmarkGPT-5.5Muse Spark 1.2Leader
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

GPT-5.5$0.020Fits in one request
Muse Spark 1.2$0.0034Fits in one request

Muse Spark 1.2 costs less

Repository review

50K input + 3K output tokens

GPT-5.5$0.340Fits in one request
Muse Spark 1.2$0.075Fits in one request

Muse Spark 1.2 costs less

Agent loop

200K input + 10K output tokens

GPT-5.5$1.30Fits in one request
Muse Spark 1.2$0.292Fits in one request

Muse Spark 1.2 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.

Specifications of GPT-5.5 and Muse Spark 1.2
SpecificationOpenAI GPT-5.5Meta Muse Spark 1.2
MakerOpenAIMeta
WeightsNo public weights listedNo public weights listed
ReleasedApril 24, 2026August 5, 2026
Context window1.05M1.05M
Input $/Mtok$5.00$1.25
Output $/Mtok$30.00$4.25
Coding index67.865.1
Independent measurements behind it22
Cost per solved task$1.65$0.64
SourceOpenRouter listingOpenRouter listing

Questions

Is GPT-5.5 better than Muse Spark 1.2 for coding?

Pick GPT-5.5 for coding: it scores 67.8 on the Vibe Coding Index against 65.1 for Muse Spark 1.2. Pick Muse Spark 1.2 when output tokens cost 7.1x less, or when a solved task costs $0.64 against $1.65.

Which is cheaper, GPT-5.5 or Muse Spark 1.2?

GPT-5.5 costs $5.00 per million input tokens and $30.00 per million output tokens; Muse Spark 1.2 costs $1.25 and $4.25. Per solved SWE-bench Verified task, GPT-5.5 costs $1.65 and Muse Spark 1.2 $0.64.

Which has the bigger context window, GPT-5.5 or Muse Spark 1.2?

GPT-5.5, with 1.05M tokens against 1.05M.

How many benchmarks is the GPT-5.5 vs Muse Spark 1.2 comparison based on?

92 benchmarks have a result for both models as of October 21, 2026. GPT-5.5's coding index rests on 2 independent benchmarks and Muse Spark 1.2's on 2. Where only one model has a result, the page says so instead of naming a winner.

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<iframe src="https://llmbenchmark.ai/embed/compare/gpt-5-5-vs-meta-muse-spark-1-2" title="GPT-5.5 vs Muse Spark 1.2, LLMBenchmark.ai" width="100%" height="360" style="border:0;max-width:100%" loading="lazy"></iframe>
<p style="font:13px/1.4 sans-serif;margin:6px 0 0">Source: <a href="https://llmbenchmark.ai/compare/gpt-5-5-vs-meta-muse-spark-1-2">LLMBenchmark.ai, GPT-5.5 vs Muse Spark 1.2</a></p>