Lowering memory use for worker MPM
 

I've recently moved from the prefork MPM to the worker MPM because there was a process limit imposed by the VPS that I was hitting.

However, contrary to what I've been hearing, memory usage increased. Most of them belong to php-cgi processes. Is there something I'm doing wrong?

I have quite a few domains (ie. vhosts) on the server, so a possibility might be because there's a different fcgi starter script for each domain?

You can wait for the upcoming ISPConfig 3.0.5 which will have support for Apache + PHP-FPM. If you use ondemand mode for PHP-FPM, workers will only be started on demand which saves a lot of memory.