Just wanted to let you know I found this plugin is making my development sites very slow on my Windows and Apache server. My staging sites on LAMP don't seem to be affected. I thought something was wrong with my server, but I did some testing and found disabling the Acunetix WP Security plugin totally fixed the speed issue - noticeably on five sites so not a fluke. My sites were painfully slow until I disabled this plugin. Without the plugin each page loads almost immediate. Kind of weird.