I'm a bit confused on why this is a problem in the first place. I'm currently taking a Blender course on Udemy and I contacted one of the admins on the course, sent my file that has the same SUBSURF lag problem, and got feedback but surprisingly this admin didn't come across the same issue when he took a look at it after I sent him the file. Apparently this is a problem only some of us are having. Does the Quality value have something to do with it? Because all of us who are familiar with the 2.7 series are familiar and can recall that the SUBSURF modifier didn't have a quality value. What is the purpose of the Quality value? I've never really noticed anything better about it compared to when Blender didn't have it.