PHP 7 Performance
PHP 7 has very advanced features such as performance, efficiency and web applications can be developed very easily for mobile and also for cloud services. The latest version PC can easily support PHP7. The key feature is that it is uses less memory. The impact is twice that of the PHP 5.6 version and consume 50% less memory compared to PHP 5.6. It consist of improved exceptions unlike the PHP 5.6. There are new operators such as null coalescing and spaceship operator and declaration. Also ZEND team has proved that it is twice faster by monitoring its performance.
The above link provides the detailed information and how to setup environment for PHP7 such parser installation and apache configuration.
Yes, the upgrade from PHP 5.6 to PHP 7 was exceptional. We used to run HHVM on a trial portal for CrazyEngineers, and PHP 7 outperformed it. It was quite impressive.