"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."