One of the most important changes in PHP 7 and the one change that i’m looking forward to with great anticipation is the over all performance boost that PHP 7 will apply. This boost will make all PHP supported CMS systems faster and all PHP sites in general, just by updating the web server to run PHP 7.
This performance boost has been archived by rewriting some of the Zend engine code and by using a more compact data structure and less heap allocations/de-allocations.
Depending on the applications and extensions you run on your web server, the new PHP 7 can Boost pages with up to 100 % in performance, while getting a smaller memory consumption. This means more performance for less RAM.
See the complete reference on github: tpunt/PHP7-Reference · GitHub
More PHP 7 performance comparisons:
Benchmarks from Rasmus’s Sydney Talk
PHP 7 release date is set to November 2015 see : https://wiki.php.net/rfc/php7timeline