centminmod performance with/without opcache, memchace, memcached, memcached server

@arlon take a read of PHP Opcode and Memcached statistics pages | Centmin Mod Community to get an overview of what's what.

They all benefit your site's performance if you web application can utilise it. Xenforo, vBulletin, Wordpress all benefit from them if they're configured correctly from their web app's respective documentation.

You can use Performance and Load Testing from the Cloud - Blitz by Spirent to benchmark sites or siege benchmark included and installed with Centmin Mod. Though siege consumes cpu and memory itself so running it on same server being tested isn't entirely accurate, best to run from separate server. Blitz.io is easiest to do.

I posted various benchmark runs on my Wordpress7 site here wordpress7.centminmod.com - Centmin Mod LEMP stack Wordpress Auto Installer on CentOS 7.0 and at Benchmarks - CentminMod.com LEMP Nginx web stack for CentOS

specific examples

• PHP 7.0.1 + Redis Cache for Wordpress (Blitz.io 10,000 user California test run on this 2GB DigitalOcean KVM VPS resulted in 302.67 million hits/day with a peak of around 5,122 hits/second and average of 3,503 hits/second.)
• WordPress Super Cache Benchmarks (Blitz.io load test) 237 million hits/day (237+ million hits/day or 7.12 billion hits per month with peak of 4,158 hits/second and an average of 2,748 hits/second. Average response time was 298ms with slowest being 882ms once it hit 7664 user mark.)

fyi, without caching, Wordpress would be lucky to be able to achieve 50-250 hits/second depending on PHP version

There is no situation really where you won't benefit greatly from implementing caching for your web app

 

yeah no much experience with WHMCS but their official documentation and support forum should have info on what type of caching to utilise for best performance