GPT-5 vs Grok 4 Fast None Reasoning
Grok 4 Fast None Reasoning offers 2.0M tokens context vs 400K tokens, Grok 4 Fast None Reasoning is more cost-effective, GPT-5 includes advanced reasoning. Compare full specs, pricing, and choose the best model for your use case.
Quick Overview
Grok 4 Fast None Reasoning
ZenMux
2.0M tokens context • $0.20 / $0.50 per 1M tokens
View full specifications →Detailed Comparison
Specification
GPT-5
Grok 4 Fast None Reasoning
Provider
ZenMux
ZenMux
Context Window
400K tokens
2.0M tokens
Max Output Tokens
128K tokens
30K tokens
Input Pricing (per 1M tokens)
$1.25
$0.20
Output Pricing (per 1M tokens)
$10.00
$0.50
Release Date
Aug 2025
Sep 2025
Capabilities
Capability
GPT-5
Grok 4 Fast None Reasoning
Text Generation
Vision
Function Calling
Advanced Reasoning
File Attachments
Which Model Should You Choose?
Choose GPT-5 if:
- • You need advanced reasoning
Choose Grok 4 Fast None Reasoning if:
- • You need a larger context window
- • Cost efficiency is a priority