AI Model Release Tracker - Timeline of Major AI Models from 2022-2026

GPT-4.5 vs Grok 4 Heavy

OpenAI
GPT-4.5
SpaceXAI
Grok 4 Heavy
Overview
CompanyOpenAISpaceXAI
Release dateFeb 27 2025Jul 9 2025
AccessProprietaryProprietary
Timeline
Release gapGPT-4.5 shipped 132 days before Grok 4 Heavy

Which is better: GPT-4.5 or Grok 4 Heavy?

GPT-4.5 and Grok 4 Heavy don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. GPT-4.5 shipped 132 days before Grok 4 Heavy, so benchmark comparisons should account for the intervening progress.

Published specifications for these two models are limited — see each model page for the latest details.

Direct benchmark comparisons are unavailable — GPT-4.5 and Grok 4 Heavy don't publish scores on any of the same benchmarks.

Frequently asked questions

GPT-4.5 was released by OpenAI on Feb 27 2025.

Grok 4 Heavy was released by SpaceXAI on Jul 9 2025.

Other comparisons