I am using EE to manage several wordpress sites and it has been working great but I have noticed that the back end of the primary/first site is getting slower. And today I was totally unable to use my sandbox site. I tried deleting every other site and creating a new wordpress with w3tc and it will not load. The main site loads fast, its backend kind of slow but useable, and everything else nothing.
I have a 2GB VPS. Memory is around 600mb and cpu usage is less than 0.1. There are no errors and the site loads painfully slow untill it times out at about 5 minuets.