Jag hittade denna guide på IBM Developerworks som verkar riktigt trevlig. Xcache är snäppet snabbare än APC (som vi använder) och laddar upp php-script i RAM för att öka prestanda.

Ursprungligen av IBM DeveloperWorks:

Don't burn cycles -- Recycle
Yet another way to conserve CPU cycles is simply to reduce the amount of rework required to run your PHP application. Certainly, there is no need to translate the same PHP code each time. After your PHP code has been translated into opcodes, it can be saved and reused again and again -- until the original code is modified. Indeed, caching -- saving and reusing the intermediate PHP code, the opcodes -- is the idea behind several PHP accelerators, including the open source Alternative PHP Cache (APC), Turck MMCache for PHP, XCache, eAccelerator, and the commercial Zend Platform. The latter three cache and optimize the byte code, providing for even greater speedups.

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