PHP 7 can help improve Drupal site performance
Drupal is PHP 7-ready and sites that run many contrib modules, or particularly memory-intensive ones, will need more memory requirements. Optimizing Drupal website performance with PHP 7 version will boost the overall page speed.
PHP 7 was released in December 2015 and offers high performance, huge load capacity and asynchronous programming support for online applications. According to the latest study, PHP 7 is twice as fast as PHP 5.6 and reduces memory usage.
Why this is the right time to move to PHP 7
Drupal 7 core officially supports PHP 5.2.5 or higher However, PHP 7 introduces backward incompatible changes which may need to be addressed in contributed or custom modules and themes. While some Drupal 7 sites may run on minimum of PHP versions, you can move to Drupal 8 with PHP 7 support to enhance the performance of the site.
Drupal 8 officially supports 200+ new features and improved functionalities, and upgrading to PHP 7 brings a lot of improvements and delivers high performance Drupal site, whether you are a website owner or a Drupal developer.
Drupal core's automated test suite is now fully passing on a variety of environments where there were previously some failures (PHP 5.4, 5.5, 5.6, and 7). Several bugs affecting those versions were fixed as well. These PHP versions are officially supported by Drupal 7 and recommended for use where possible.
Anecdotal evidence from a variety of users suggests that Drupal 7 can be successfully used on PHP 7, both before and after the 7.50 release.
A slow website load time impacts visitors, overall user experience, and the bottom line. With the improved speed enhancements of Drupal 7 and Drupal 8 with PHP 7, your user engagement and experience will increase and less likely they will leave your website