Quick note to say THANKS!
We used w3tc in the past (yes, we configured it properly, so for the fanboys out there don’t get me started on that plugin, we use it on several servers, for some reason it just doesn’t play well with some configs, e.g. extreme load as many pages would not be cached due to cookie management issues, etc…).
We decided to switch to supercache, after a day we already see a huge improvement on a low end machine. Also note that supercache handles mirror CDNs better than w3tc, as ALL JS and CSS requests are now sent to the CDN, while w3tc was only able to catch half of them (not sure why).