There might be many factors affecting your performance, I have servers running heavy loads. I also have one server running over 75 sites so it depends on your tweaking.
You may also have to configure MySQL to ensure you are not getting deadlocked there.
Also Wordpress depending on your number of plugins and the type of plugins will also cause high load.
You should also configure your litespeed plugin efficiently and ensure to use lsmcd (memcached).
N.B. None of my servers has that amount of RAM
To fix the issue with the login page, you can follow this solution.