Every programmers have already experienced a "Fatal error: Allowed memory size of xxx bytes exhausted" error message. This talk is highly technical and will explain the attendees how memory works inside PHP with understandable words and schemas. We'll start by refreshing minds about what memory is, and how it works on the system and then focus on PHP case by introducing its main memory component known as "Zend Memory Manager". You'll discover how PHP uses memory and above all : how you can figure it out into your everydays scripts and how you can be more efficient about it.