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

Grok 4 Heavy vs GLM-5.1

SpaceXAI
Grok 4 Heavy
Z.ai
GLM-5.1
Overview
CompanySpaceXAIZ.ai
Release dateJul 9 2025Apr 7 2026
AccessProprietaryOpen Weight
Specifications
Parameters
744B
Context window
200k
Benchmarks
Nonsense detection
BullshitBench v2
22%
Next.js coding
Next.js Evals
75%
Agentic terminal coding
Terminal-Bench 2.0
63.5%
Web browsing
BrowseComp
68%
Multidisciplinary reasoning
Humanity's Last Exam · with tools
52.3%
Science
GPQA Diamond
86.2%
Community preference (code)
Arena Elo (Code)
1527
Timeline
Release gapGrok 4 Heavy shipped 272 days before GLM-5.1

Which is better: Grok 4 Heavy or GLM-5.1?

Grok 4 Heavy and GLM-5.1 don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Grok 4 Heavy shipped 272 days before GLM-5.1, so benchmark comparisons should account for the intervening progress.

Grok 4 Heavy is proprietary, while GLM-5.1 is open weight.

Direct benchmark comparisons are unavailable — Grok 4 Heavy and GLM-5.1 don't publish scores on any of the same benchmarks.

Frequently asked questions

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

GLM-5.1 was released by Z.ai on Apr 7 2026.

Grok 4 Heavy is a proprietary model released by SpaceXAI. GLM-5.1 is an open weight model released by Z.ai.

Other comparisons