UPDATE: MAY 18TH 2018
We no longer support HHVM on SiteGround servers!
We're happy to announce that HHVM is now being added as an option to our Cloud hosting platform. HHVM is a great technology that uses a just-in-time compilation approach to achieve superior speed when handling PHP scripts and thus makes PHP-based websites faster.
Why should you consider using HHVM?
One word - speed. HHVM is considerably faster than every 5.x PHP currently available. There are a lot of in-depth performance tests of HHVM versus different PHP versions floating around showing this result. I really don't want to repeat any of those, but just to give you an idea about the performance boost you can get, I've done a simple and quick test. First, I measured the loading time for the dynamic part of a default WordPress installation with a lot of sample data and the twentyfifteen theme, and the result was approximately 400ms with PHP 5.6. Then, I switched the very same application to use HHVM and that time dropped down to about 200ms. This means that the dynamic part of the loading process was approximately twice faster with HHVM. It should be also noted that this test was done when the dynamic cache was switched off. If you already use dynamic cache, enabling HHVM will probably not have a dramatic effect on the pages of your site that are cached, simply because their loading no longer relies on the speed of the PHP handling. However, HHVM will improve the speed for the parts of your site that are not suitable for dynamic caching, for example your WordPress administrative area, your shopping cart pages, etc. So for best speed results we recommend using both technologies together.
Using HHVM on SiteGround
All new cloud accounts will be setup from now on to include HHVM as an option. We will soon add the technology to all existing Linux container based Cloud accounts too. The HHVM can be activated through a new tab in our SuperCacher tool in the cPanel as explained in our HHVM tutorial.