I installed PHP5.3.3 and PHP5.4.28 at the same time in one VirtualBox guest OS.
- Host OS: Windows 7 Ultimate 64bit
- VirtualBox 4.3.12
- Guest OS: CentOS 6.5 64bit with 512MB base memory
- PHP5.3.3 is installed as mod_php
- PHP5.5.12 is installed as php-fpm with mod_fastcgi
Run PHP BENCHMARK SCRIPT to get the total time.
The total time of PHP 5.3.3 is 6.746 seconds.
The total time of PHP 5.5.12 is 5.628 seconds.
I repeated the test many times. The average difference is 85%. On the other words, PHP 5.5 spend 1 second less than PHP 5.3.