"Nginx is known to be slow while serving dynamic pages like php. Normally, nginx is using fast-cgi method which is slow. Therefore, it's a good idea to run Apache as back-end server to Nginx and serve dynamic php pages from Apache. If your website's php pages suitable to cache for a certain time, you can use Nginx proxy module and proxy_store command to cache Apache served php pages output in Nginx automatically as html.
"Here, I'll give you instructions how to use Nginx's memcache module and Danga Software's memcached deamon to store your content in memory and serve it. Serving content from memory will be faster than serving it from disk. memcached's default listening port is 11211. You can find instructions on Danga Software's website how to compile and run memcached."
