PHP Benchmark
PHPBench.org
When it comes to optimizing PHP for performance, there are endless resources available. PHPBench was constructed as a way to open people’s eyes to the fact that not every PHP script will run at the same speed.
NOTE: You must keep in mind to refresh this page a few times to “catch” the right result. The numbers change sometimes drastically during each refresh.
While most of the tests show trivial performance differences, there are some surprising results. For example, if you implement sizeof() there is almost no difference in whether calculating the size of a loop in advance.
Link: http://www.phpbench.com/