Most Memory Efficient Setup for VPS with Shared Wordpress Webhosting

Hi guys,
I am new to Centos Web Panel and am coming from a Webmin/Virtualmin system. Virtualmin is extremely powerful and has some really great features, however, my main reason for considering a complete changover is a lack of forum responses and a user interface that is essentially an illogical confusing mess. IF its difficult for me, my clients havent a hope.

So with the above in mind, i wish to thank the developers of CWP for a great interface (particularly the client side one...its brilliant)

My current CWP system specs

Vultr VPS
2 V/Core CPU
4GB RAM
Bandwidth 3 TB
Storage 80GB SSD

What i have begun to notice about running shared hosting clients on VPS is that the most significant system need is RAM. I run out of available RAM long before i get anywhere near using up storage, cpu, or bandwidth.

I mainly host Wordpress websites (and some static html sites)

What is the most memory efficent configuration for Shared Wordpress Hosting?

At present i have setup Nginx & Apache+Varnish (both running FPM v 7.3). I was wondering if i wouldnt be better instead going with just Nginx?

kind regards
Adam

It's not possible to precisely to define "the most memory efficent configuration for Shared Wordpress Hosting" in any server.
You can have several specific needs.
As much memory your would you have on your server, it's better.

But you can optimize other areas.
For example, I installed Rspamd.
I could to save 1 Gb memory.
So I disable the amavisd, policyd-spf, opendkim, and spamassassin (I think it's a greedy memory eater).
I'm suspect, because I posted a Rspamd howto in this forum.

But with no one optimizations in my customer's sites, I'm running several Wordpress sites, in two VPS servers with exactly identical configuration as you, and I have no problems other than normal security worries.

Regards,
Netino

I actually ran some server loads tests on identical websites on two VPS. I used the Paessler load test software.

To be honest, i found that on lower end systems (ie 1CPU, 2GB Ram), running Nginx+VArnish+Apache is a bad idea. Any significant load and the VPS craps itself making both the CWP control panel, and websites on the server non functional (throws mysql and memory erros in users browsers).

The best setup i have found so far is just plain old nginx on its own.

Having said that, the results of my tests completed last nite on two VPS's with same resource allocations are found here...https://drive.google.com/open?id=1efdBqBDRVc8lAtDpTOp9velzS7rfOVlm

I found in all honesty, lightspeed remains stable even under heavy loads where nginx stops serving.