FastDup literally work well on a minimally low server configuration. However, it is important to note that the overall best performance of any WordPress plugin would be achieved through a well optimized server configuration. Some of the other minimum requirements include the following:
Supported web servers; Nginx, Apache, LiteSpeed, Lighttpd, IIS, uWSGI and WebServerX.
MS Edge, Firefox, Safari or Chrome for admin panel.
Configurable maximum execution time for PHP