I've tried searching a lot and basically here is the problem. I have a website but I'm unable to pin point the reasons of why the performance of the website is so slow. We have shifted to a high end server separated the webserver and the database server.
MySQL Caching, HTML / CSS & JS minification is done , All basic issues which Google Speed test and GTmetrix could give is also done but still the initial loading of the website itself takes 3-10 seconds. Some pages load very slow is there any kind of application or server management tool which we can use to track and see what is actually slowing up and then work on fixing it ?