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AI Choice Engine

Model comparison

Muse Spark 1.2 vs Upstage Solar Pro 4

Meta against Upstage, compared on context, price, and verified benchmark results.

Catalog record checked September 26, 2026Individual provider fields may changeEvidence confidence: High — see receipts below

Meta

Muse Spark 1.2

Frontier

vs

Upstage

Upstage Solar Pro 4

Frontier

AI model capability comparison
SpecificationMuse Spark 1.2Upstage Solar Pro 4
ProviderMetaUpstage
TierFrontierFrontier
Context windowWinner: 1.05M524K
Max outputNot verifiedUnverified128K
Input / 1M tokens$1.25Winner: $0.30
Output / 1M tokens$4.25Winner: $1.20
WeightsClosedClosed
ParametersMeta frontier modelNot disclosedUnverified
Reasoning levelsminimal, low, medium, high, xhigh, maxlow, medium, high
Modalitiestext, image, video, audio, pdftext
API model idmuse-spark-1.2solar-pro4
ReleasedAugust 5, 2026August 10, 2026
Artificial Analysis Intelligence Index [xhigh] (2026-09-26)39.6Not verifiedUnverified
Artificial Analysis Intelligence Index (2026-09-26)Not verifiedUnverified28.2

Prices are USD per million tokens at standard rates, excluding batch and caching discounts. Bold indicates the better figure where one is objectively better. Values we could not confirm from the provider are shown as “Not verified” rather than estimated.

Benchmark receipts

Where each score comes from, and how far it can be compared across models.

  • 2026-09-26
    Artificial Analysis (AA-estimated)

    Composite index blending reasoning, knowledge, and coding evals into one 0–100 score.

    Comparable with caveatOnly same-version scores are comparable. v4.3.2 was rebaselined (the top score fell from 66 on v4.1.1 to ~58), so v4.1.1 figures must not be compared with v4.3.2 figures — check measuredAt.

Pricing tiers

Muse Spark 1.2: $1.25/$4.25 per MTok on Meta's Model API (Standard tier shared with Muse Spark 1.3; cached input $0.15). Closed weights.

Upstage Solar Pro 4: List $0.30/$1.20 per MTok; cached input $0.06. The 90%-off launch promo ended 2026-09-10. Closed API. 524K context with up to 128K output.

FrontierRecord checked September 26, 2026

Muse Spark 1.2

Muse Spark 1.2 is Meta's closed frontier model until the 1.3 refresh (2026-09-02) — still served and ranked in the LMArena text top 10 as of mid-2026.

Best for

  • Frontier reasoning
  • Meta ecosystem
  • Agentic work

Watch out

Closed-weights (unlike Llama 4); Meta's post-Llama-4 frontier branding.

FrontierRecord checked September 26, 2026

Upstage Solar Pro 4

Solar Pro 4 is Upstage's closed flagship with a 524K context at a low $0.30/$1.20 list price.

Best for

  • Long-context
  • Cost-sensitive API
  • Korean + English

Watch out

Closed API; the launch promo has ended, so budget at the $0.30/$1.20 list rate.

When the cheaper one wins

Upstage Solar Pro 4 is cheaper on output at $1.20 per million tokens against $4.25 for Muse Spark 1.2 — about 3.5×. Use the cheaper tier for classification, extraction, summarisation, and any task where the expensive model’s extra score does not change the accepted output. The expensive one only pays if your hardest task actually fails on the cheap tier. These are standard-tier API rates, excluding batch and cache discounts.

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Evidence confidence: High

How strong and complete the evidence behind this comparison is — not a prediction of which model is better.

  • Pricing verified on both sides — Input and output rates are verified for both models.
  • 3/5 core specs verified on both sides — Not published for at least one side: max output, parameter count.
  • 1 shared named benchmark with differing scores — Measured on: Artificial Analysis Intelligence Index.
  • Verified within the last 90 days — Newest catalog check was 2 days ago.
  • Both models carry source citations — Each side has at least two catalog sources on record.

Source receipts

Each catalog figure was checked against the provider or an independent second source on the date shown.

Related comparisons

Diving deeper on one model? Muse Spark 1.2 · Upstage Solar Pro 4

Common questions

Muse Spark 1.2 vs Upstage Solar Pro 4

Answered from the verified figures on this page rather than general guidance.

Is Muse Spark 1.2 or Upstage Solar Pro 4 cheaper for input?
Upstage Solar Pro 4 is cheaper at $0.30 per million input tokens, against $1.25 for Muse Spark 1.2 — roughly 4.2× the price. Output tokens usually dominate a real bill, so weigh the output rate more heavily than the input rate. These are base rates; Muse Spark 1.2 has tiered pricing: $1.25/$4.25 per MTok on Meta's Model API (Standard tier shared with Muse Spark 1.3; cached input $0.15). Closed weights. Upstage Solar Pro 4 has tiered pricing: List $0.30/$1.20 per MTok; cached input $0.06. The 90%-off launch promo ended 2026-09-10. Closed API. 524K context with up to 128K output.
Is Muse Spark 1.2 or Upstage Solar Pro 4 cheaper for output?
Upstage Solar Pro 4 is cheaper at $1.20 per million output tokens, against $4.25 for Muse Spark 1.2 — roughly 3.5× the price. Output tokens usually dominate a real bill, so weigh the output rate more heavily than the input rate. These are base rates; Muse Spark 1.2 has tiered pricing: $1.25/$4.25 per MTok on Meta's Model API (Standard tier shared with Muse Spark 1.3; cached input $0.15). Closed weights. Upstage Solar Pro 4 has tiered pricing: List $0.30/$1.20 per MTok; cached input $0.06. The 90%-off launch promo ended 2026-09-10. Closed API. 524K context with up to 128K output.
Which has the larger context window, Muse Spark 1.2 or Upstage Solar Pro 4?
Muse Spark 1.2 accepts 1.05M tokens against 524K for Upstage Solar Pro 4. This only matters if you routinely send very long documents or large codebases.
Do Muse Spark 1.2 and Upstage Solar Pro 4 support the same reasoning levels?
Muse Spark 1.2 exposes minimal, low, medium, high, xhigh, max, while Upstage Solar Pro 4 exposes low, medium, high.
Should I use Muse Spark 1.2 or Upstage Solar Pro 4?
Both sit in the frontier tier, so the choice usually comes down to price and context rather than capability. Muse Spark 1.2 suits frontier reasoning; Upstage Solar Pro 4 suits long-context.

Next step

Choosing between them

The verified figures that separate this pair, computed from the catalog rather than restated boilerplate.

  • Input price: Upstage Solar Pro 4 costs $0.30 per 1M tokens versus $1.25 for Muse Spark 1.2 — a 4.2x difference at the headline tier.
  • Context: Muse Spark 1.2 takes 1.05M against 524K for Upstage Solar Pro 4 — only decisive if your prompts approach the smaller window.
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