PHP handler type

For an out-of-the-box config, you’re going to get far better performance from Nginx than Apache. If you’re an old-school Apache sysadmin who can tweak Apache to the bone, then the jury is out there. But then you wouldn’t also be here asking for advice ??

In fact, the commonly-cited situation for choosing Apache over (or in conjunction with) Nginx is where there are legacy .htaccess rules that can’t (easily) be ported to their Nginx equivalent… as Nginx ignores these directives. But in more than a decade that I’ve managed WordPress sites and servers, I’m yet to encounter any such situation. So these days I ONLY run Nginx with no Apache at all.

Now to “FPM” vs “Dedicated FPM”. This is a per-site Plesk config, and the difference is:

— Dedicated FPM by Nginx/Apache: Here, the individual website that this setting is configured for uses its own PHP-FPM process.

— FPM by Nginx/Apache: Here the sites uses the same global PHP-FPM process that serves all websites that use a particular PHP version.

If your CPU is maxed out already, it wouldn’t matter much whether you use a single FPM process for all sites or give each site its own process. The only benefit to using dedicated FPM, in this case, would be better isolation and sharing of the server resources as desired and preventing one site from hugging the server.

You could, of course, tweak and optimize your WordPress/theme/plugin calls, as well as MySQL server, Apache/Nginx, and PHP configs to squeeze more out of your current server. But that’s way outside the scope of this support forum.

Good luck!

Don’t want to state the obvious, but it might be a good idea to run tests after switching to each option.

Also, I’d recommend getting to know those handlers by learning about Apache and nginx (either via YouTube videos or Udemy courses) because you can achieve great results (in terms of performance) with either option – you just need to know how to configure them well.