Please read How to Set Preferences & Memory Usage for Peak Performance before you continue reading this article.
History & Caches
Simply put, keep History States and Cache Levels at their default settings, and get into the habit of working on separate Layers,...
Here are a few ways to enhance Photoshop performance:
Optimize your current hardware
Customize Performance Preferences in Photoshop
Tailor your Photoshop work habits (read more: History, Caches & Performance-Friendly Work Habits)
The faster the processor you’re using and the more random...