I just had this happen to me. I have an R7 5800x and I had TWO Vortex processes running, one with 5 instances total and one by itself. I haven't had any crashes, I do not have it start on startup. I closed the vortex window, and the 5 instances closed, but the ONE that was by itself stayed open. It, however, was using over 15%, averaging 18% by ITSELF of my 16 thread CPU at 4Ghz+. I "idle" at between 4% and 5% CPU usage for running browsers, and 8% watching YouTube, I fail to see how an instance of vortex should be open and using 18% of my CPU by itself when it is closed. Pushing my CPU to over 25% total usage when closed doesn't make me very happy, wondering if this is why some of my games have been running poorly.