Model comparison

GPT-5.6 Sol vs Muse Spark 1.2

GPT-5.6 Sol is the stronger model overall, scoring 64.4 to 49.8 on the Noometry Index. Muse Spark 1.2 costs 4.0× less per token, which makes it the better buy when GPT-5.6 Sol's lead doesn't matter for your workload.

Last verified . 28 shared benchmarks.

GPT-5.6 Sol OpenAI

64.4

Rank #6 Confirmed

Muse Spark 1.2 Meta

49.8

Rank #44 Confirmed

Summary

  • They share 28 benchmarks with published results for both. GPT-5.6 Sol scores higher in 8 categories and Muse Spark 1.2 in 2 categories; 7 gaps are clear of the uncertainty.
  • The widest gap is in math, where GPT-5.6 Sol leads 85.5 to 43.8.
  • The biggest single-benchmark swing is ProofBench: 83% for GPT-5.6 Sol and 43% for Muse Spark 1.2.
  • Muse Spark 1.2 is cheaper at $1.25 / $4.25 per million input/output tokens, against $4 / $20 for GPT-5.6 Sol.
  • GPT-5.6 Sol accepts more context: 1.05M tokens versus 1.05M.

Side by side

GPT-5.6 Sol and Muse Spark 1.2 specifications
GPT-5.6 SolMuse Spark 1.2
ProviderOpenAIMeta
Noometry Index64.449.8
Released2026-07-092026-08-05
WeightsProprietaryProprietary
Context window1.05M1.05M
Max output128K131K
Input $ / M tokens$4$1.25
Output $ / M tokens$20$4.25
Results tracked6428

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Category by category

Coding GPT-5.6 Sol leads

GPT-5.6 Sol: 61.1 (#7), Muse Spark 1.2: 48.6 (#49)

Coding benchmarks
BenchmarkGPT-5.6 SolMuse Spark 1.2
DeepSWE72.7%54.9%
LMArena WebDev16191532
FrontierSWE32.2%12%
SciCode57.1%56.4%
WeirdML89.4%60.3%
LMArena Coding14931497
FrontierCode47.5%—
CursorBench41.7%—
MirrorCode20%—
ALE-Bench2,177—

Agentic & Tool Use GPT-5.6 Sol leads

GPT-5.6 Sol: 50.2 (#7), Muse Spark 1.2: 29.5 (#77)

Agentic & Tool Use benchmarks
BenchmarkGPT-5.6 SolMuse Spark 1.2
APEX-Agents51.4%36.4%
GDP.pdf30.7%16%
OSWorld 2.027.3%—
τ²-bench Banking46.9%—
PostTrainBench36.2%—
BALROG60%—
GBAEval52.6%—
LMArena Search1257—
Vending-Bench 29,619—

Reasoning GPT-5.6 Sol leads

GPT-5.6 Sol: 74.7 (#6), Muse Spark 1.2: 50.4 (#32)

Reasoning benchmarks
BenchmarkGPT-5.6 SolMuse Spark 1.2
SimpleBench71.7%74.5%
NYT Connections (extended)93.8%79.2%
CritPt32.3%17.7%
LMArena Hard Prompts14811490
DTBench96%94.7%
LMCA59.2%48.4%
Epoch Capabilities Index161.99155.18
ARC-AGI-292.5%—
Kagi LLM Benchmark67%—
ARC-AGI-197.5%—
Chess Puzzles64%—
EnigmaEval37.1%—
EBR-Bench44.8%—
Mystery Game Puzzles58%—
Surface Evolver Bench93.1%—
Bench to the Future 30.14—

Math GPT-5.6 Sol leads

GPT-5.6 Sol: 85.5 (#7), Muse Spark 1.2: 43.8 (#68)

Math benchmarks
BenchmarkGPT-5.6 SolMuse Spark 1.2
ProofBench83%43%
FrontierMath (Tiers 1-3)89.1%—
FrontierMath Tier 482.9%—
OTIS Mock AIME 2024-2025100%—
LMArena Math1472—
FrontierMath Erdős0%—

Knowledge GPT-5.6 Sol leads

GPT-5.6 Sol: 64.3 (#16), Muse Spark 1.2: 53.9 (#49)

Knowledge benchmarks
BenchmarkGPT-5.6 SolMuse Spark 1.2
SimpleQA Verified69.7%60.3%
LMArena Expert15171485
GPQA Diamond93.5%—
Vectara Hallucination Rate12.4%—

Multimodal GPT-5.6 Sol leads

GPT-5.6 Sol: 48.9 (#8), Muse Spark 1.2: 42.6 (#24)

Multimodal benchmarks
BenchmarkGPT-5.6 SolMuse Spark 1.2
LMArena Vision12811304
Blueprint-Bench 233.6%—
Furniture Assembly56.7%—
LMArena Document1483—

Multilingual Muse Spark 1.2 leads

GPT-5.6 Sol: 55.4 (#32), Muse Spark 1.2: 57.4 (#10)

Multilingual benchmarks
BenchmarkGPT-5.6 SolMuse Spark 1.2
LMArena Non-English14501479
LMArena Chinese15231519
LMArena Russian14661494
LMArena French1475—
LMArena German1476—
LMArena Japanese1475—
LMArena Korean1434—
LMArena Spanish1449—

Instruction Following Too close to call

GPT-5.6 Sol: 77.8 (#16), Muse Spark 1.2: 77.1 (#30)

Instruction Following benchmarks
BenchmarkGPT-5.6 SolMuse Spark 1.2
LMArena Instruction Following14801466

Long Context Too close to call

GPT-5.6 Sol: 45.3 (#42), Muse Spark 1.2: 45.4 (#35)

Long Context benchmarks
BenchmarkGPT-5.6 SolMuse Spark 1.2
LMArena Longer Query14791483

Writing & Preference Too close to call

GPT-5.6 Sol: 73.5 (#12), Muse Spark 1.2: 72.6 (#14)

Writing & Preference benchmarks
BenchmarkGPT-5.6 SolMuse Spark 1.2
LMArena Text14561486
LMArena Creative Writing14501444
EQ-Bench Creative Writing19721840
LMArena Multi-Turn14561504
EQ-Bench 41250—

Frequently asked questions

Is GPT-5.6 Sol better than Muse Spark 1.2?

GPT-5.6 Sol is the stronger model overall, scoring 64.4 to 49.8 on the Noometry Index. Muse Spark 1.2 costs 4.0× less per token, which makes it the better buy when GPT-5.6 Sol's lead doesn't matter for your workload.

Which is cheaper, GPT-5.6 Sol or Muse Spark 1.2?

Muse Spark 1.2 is cheaper. It lists at $1.25 per million input tokens and $4.25 per million output tokens; GPT-5.6 Sol lists at $4 and $20.

Is GPT-5.6 Sol or Muse Spark 1.2 better for coding?

GPT-5.6 Sol scores higher on coding benchmarks: 61.1 versus 48.6 in the Noometry coding category.

Which has the bigger context window?

GPT-5.6 Sol does, with 1.05M tokens against 1.05M.

How many benchmarks do GPT-5.6 Sol and Muse Spark 1.2 share?

28 benchmarks have published results for both models. GPT-5.6 Sol has 64 scored results on Noometry and Muse Spark 1.2 has 28.

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