I’ve recently had to abandon using eaccelerator because they are just not keeping up anymore with PHP releases and they even removed variable data cache support just to get PHP 5.3 compatibility. It’s sad because they were the fastest and most stable for years.
So I have been testing xcache and APC instead.
One trick I use on large/active servers for an additional performance boost is to turn off the file stat feature on the PHP opcode cache. This makes it stop checking the timestamp on each and every PHP file executed. WordPress for example has over 100 php files totaling nearly 3 megabytes on a typical install.
You’d use ONE of these directives in php.ini depending which opcode cache you use: