The issue: It's hard to find the bottleneck Even best designed and coded apps maybe slow Finding the bottleneck is sometimes really hard Trial and error is time consuming The solution: Profile your code A profiler shows you, which parts of your code consumes how many time The Xdebug debugger already contains a profiler Profiling shows you the bottlenecks in overview Recommendation: Profiler Xdebug (open source) http://xdebug.org APD (open source) http://pecl.php.net/package/apd