To what degree can use of caching-plugins and a CDN boost WordPress performance? [closed]

If your content is rarely updated and that you have configured a caching solution to have what is commonly called a ‘supercache’.

This means that ounce a page is cached, next call to that page will return a static content, without requiring a call to a php interpreter.

Even on a cheap hosting, you can hold some huge traffic (over 1000 hits/s) and your next limit will then be bandwidth.