Slydeways has many builtin features that make it one of the fastest themes on the market.
There is a section in the customizer named: Speed Optimization
It has three different settings for speeding up your website.
Use Font Awesome CDN (recommended)
This theme ships with all the fonts and assets needed without the need for CDN’s, However you can use CDN’s (Content Delivery Networks) to speed up downloading times for users. This change affects the the Font Awesome Icons.
The Font Awesome fonts can be downloaded from the CDN by just gong Customize > Font Styles > Use Font Awesome CDN.
Optimize & Style Simple Colorbox Plugin
This is only needed if you are using the Simple Colorbox Plugin.
Load jQuery in Footer (recommended)