What is the difference between GPT-4.5 and Muse Spark 1.3?

GPT-4.5 is developed by OpenAI while Muse Spark 1.3 is developed by Meta AI. GPT-4.5 has a 128K token context window vs Muse Spark 1.3's 1.0M. You can compare their actual outputs across 24 challenges on Rival to see how they differ in practice.

Which is better, GPT-4.5 or Muse Spark 1.3?

It depends on your use case. GPT-4.5 and Muse Spark 1.3 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 24 challenges so you can judge which fits your needs best.

How much does GPT-4.5 cost compared to Muse Spark 1.3?

GPT-4.5 costs $75/M input tokens and Muse Spark 1.3 costs $1.25/M input tokens. Muse Spark 1.3 is $73.75/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

How can I compare GPT-4.5 and Muse Spark 1.3 on Rival?

This page shows a side-by-side comparison of GPT-4.5 and Muse Spark 1.3 across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

Updated Sep 2026

GPT-4.5vsMuse Spark 1.3

Muse Spark 1.3 is cheaper than GPT-4.5 at $1.25/M vs $75/M input tokens.

GPT-4.5 and Muse Spark 1.3 compared across 24 shared prompts
Spec	GPT-4.5	Muse Spark 1.3
Input price	$75/M tokens	$1.25/M tokens
Output price	$150/M tokens	$4.25/M tokens
Context window	128K tokens	1.0M tokens
Weights	—	Closed
Free API (OpenRouter)	No	No
Released	Feb 2025	Sep 2026