Model comparison

GPT-5.5 vs Muse Spark 1.3

GPT-5.5 is the stronger model overall, scoring 63.4 to 54.4 on the Noometry Index. Muse Spark 1.3 costs 5.6× less per token, which makes it the better buy when GPT-5.5's lead doesn't matter for your workload.

Last verified . 33 shared benchmarks.

GPT-5.5 OpenAI

63.4

Rank #8 Confirmed

Muse Spark 1.3 Meta

54.4

Rank #27 Confirmed

Summary

  • They share 33 benchmarks with published results for both. GPT-5.5 scores higher in 7 categories and Muse Spark 1.3 in 3 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in knowledge, where GPT-5.5 leads 64.4 to 42.0.
  • The biggest single-benchmark swing is Mystery Game Puzzles: 56% for GPT-5.5 and 25% for Muse Spark 1.3.
  • Muse Spark 1.3 is cheaper at $1.25 / $4.25 per million input/output tokens, against $5 / $30 for GPT-5.5.
  • GPT-5.5 accepts more context: 1.05M tokens versus 1.05M.

Side by side

GPT-5.5 and Muse Spark 1.3 specifications
GPT-5.5Muse Spark 1.3
ProviderOpenAIMeta
Noometry Index63.454.4
Released2026-04-232026-09-02
WeightsProprietaryProprietary
Context window1.05M1.05M
Max output128K131K
Input $ / M tokens$5$1.25
Output $ / M tokens$30$4.25
Results tracked7134

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Category by category

Coding GPT-5.5 leads

GPT-5.5: 58.3 (#13), Muse Spark 1.3: 56.1 (#18)

Coding benchmarks
BenchmarkGPT-5.5Muse Spark 1.3
LMArena WebDev15121655
SciCode56.1%59.7%
LMArena Coding14941516
SWE-bench Verified80.6%—
DeepSWE67%—
FrontierCode43%—
CursorBench—41.6%
GSO40.2%—
WeirdML84.9%—
MirrorCode10%—
ALE-Bench1,943—

Agentic & Tool Use GPT-5.5 leads

GPT-5.5: 50.7 (#6), Muse Spark 1.3: 38.6 (#28)

Agentic & Tool Use benchmarks
BenchmarkGPT-5.5Muse Spark 1.3
APEX-Agents55.1%57.8%
GDP.pdf26%27.6%
Terminal-Bench84.7%—
OSWorld 2.013%—
Remote Labor Index6.3%—
τ²-bench Banking44.6%—
DeepResearch Bench54%—
PostTrainBench27.2%—
ExploitBench47.4%—
GBAEval53.2%—
LMArena Search1242—
Vending-Bench 27,524—

Reasoning GPT-5.5 leads

GPT-5.5: 72.7 (#8), Muse Spark 1.3: 52.9 (#27)

Reasoning benchmarks
BenchmarkGPT-5.5Muse Spark 1.3
NYT Connections (extended)96.2%85.1%
CritPt27.1%24.9%
Chess Puzzles54%38%
LMArena Hard Prompts14891503
Mystery Game Puzzles56%25%
DTBench96%96.5%
LMCA54.3%53.9%
Bench to the Future 30.140.14
Epoch Capabilities Index159.25156.89
ARC-AGI-285%—
SimpleBench69%—
Kagi LLM Benchmark88.8%—
ARC-AGI-195%—
EBR-Bench34.3%—
Surface Evolver Bench88.1%—
ForecastBench60.6—

Math GPT-5.5 leads

GPT-5.5: 81.5 (#9), Muse Spark 1.3: 72.4 (#16)

Knowledge GPT-5.5 leads

GPT-5.5: 64.4 (#14), Muse Spark 1.3: 42.0 (#92)

Knowledge benchmarks
BenchmarkGPT-5.5Muse Spark 1.3
LMArena Expert15081516
GPQA Diamond94%—
SimpleQA Verified63%—
Vectara Hallucination Rate9.3%—

Multimodal GPT-5.5 leads

GPT-5.5: 47.1 (#11), Muse Spark 1.3: 43.0 (#21)

Multimodal benchmarks
BenchmarkGPT-5.5Muse Spark 1.3
LMArena Vision12971310
LMArena Document14861471
Blueprint-Bench 236.2%—
Furniture Assembly44.2%—

Multilingual Muse Spark 1.3 leads

GPT-5.5: 56.5 (#19), Muse Spark 1.3: 57.8 (#6)

Multilingual benchmarks
BenchmarkGPT-5.5Muse Spark 1.3
LMArena Non-English14671485
LMArena Chinese15351527
LMArena French14861534
LMArena Korean14611513
LMArena Russian14731491
LMArena Spanish14691485
LMArena German1478—
LMArena Japanese1498—

Instruction Following Too close to call

GPT-5.5: 77.7 (#18), Muse Spark 1.3: 77.8 (#14)

Instruction Following benchmarks
BenchmarkGPT-5.5Muse Spark 1.3
LMArena Instruction Following14791481

Long Context GPT-5.5 leads

GPT-5.5: 48.3 (#12), Muse Spark 1.3: 45.7 (#29)

Long Context benchmarks
BenchmarkGPT-5.5Muse Spark 1.3
LMArena Longer Query14841491
CL-bench Life22.2%—

Writing & Preference Too close to call

GPT-5.5: 72.8 (#13), Muse Spark 1.3: 73.7 (#10)

Writing & Preference benchmarks
BenchmarkGPT-5.5Muse Spark 1.3
LMArena Text14711490
LMArena Creative Writing14551450
EQ-Bench Creative Writing18441906
LMArena Multi-Turn14771486
EQ-Bench 41315—

Frequently asked questions

Is GPT-5.5 better than Muse Spark 1.3?

GPT-5.5 is the stronger model overall, scoring 63.4 to 54.4 on the Noometry Index. Muse Spark 1.3 costs 5.6× less per token, which makes it the better buy when GPT-5.5's lead doesn't matter for your workload.

Which is cheaper, GPT-5.5 or Muse Spark 1.3?

Muse Spark 1.3 is cheaper. It lists at $1.25 per million input tokens and $4.25 per million output tokens; GPT-5.5 lists at $5 and $30.

Is GPT-5.5 or Muse Spark 1.3 better for coding?

GPT-5.5 scores higher on coding benchmarks: 58.3 versus 56.1 in the Noometry coding category.

Which has the bigger context window?

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

How many benchmarks do GPT-5.5 and Muse Spark 1.3 share?

33 benchmarks have published results for both models. GPT-5.5 has 71 scored results on Noometry and Muse Spark 1.3 has 34.

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