Two days ago, one of the PHP developers Dmitry Stogov (dmitry + at + zend + dot + com) published the results of tests of the new version of php 5.3
He does not describe which tests he produced, but the statistics are impressive. Drupal 20% faster Qdig 2% faster typo3 30% faster wordpress 15% faster xoops 10% faster
PHP 5.3 will be faster (http://news.php.net/php.internals/36484)