The first step when optimizing PrestaShop is to make sure that you use the latest version of PrestaShop (and at least 22.214.171.124 or newer) which support PHP 8.
Using PHP8 with opcode caching (available by default with our Linux Shared Hosting plans) will give you an extra boost in performance right from the start.
If you can't use the latest version of PrestaShop or you need to use release older than 126.96.36.199 we recommend that you use at least PHP version 5.5 or 5.6 with opcode caching enabled (available by default with our Linux Shared Hosting plans).
To change your PHP version and make sure that you use opcode caching, in our latest Linux Shared hosting packages, please follow the tutorial as outlined below:
Once you set the right PHP version and opcode caching, please follow the official PrestaShop optimization tutorial: Performance Parameters
Please, note that APC is the same as opcode caching, you should leave the Caching outlined in the article to FileSystem based, we do not support xcache on shared hosting accounts
If you are using other packages, such as VPS/Cloud we recommend that you look into the PHP version, and opcode caching. If you are using cPanel/WHM you can re-compile your EasyPache to use latest PHP version and opcode caching following the tutorial at: