Most slowdowns start with things being loaded on boot that the user is not aware of.
With these commercially sold computers from manufacturers, there is a ton of garbage that is loaded on the drive that generates extra money for them. Trialware, adware, "helper" overlays for system configurations and other junk are loaded on boot. The problem with reinstalling Windows from a recovery partition is that same garbage gets re-loaded fresh and you must deal with it again.
In addition to the above, over time and various software program installations many programs install update checkers to see if a newer version of that program is available. These updaters check every time you boot the computer or when you boot that program and then just sit there doing nothing except eating clock cycles off the CPU. The majority of these can be removed, and you can manually check for updates occasionally. Many programs load a system tray icon so you can ID some of them from there.
For years I have been removing these from clients' computers and their units start running fast again; it's pretty amazing the difference it makes, plus freeing up hundreds of mega of storage on your computer.
You can start by enterint Task Manager, and identifying the various things posted there. You can Google-search most of them. If you are interested, we can go further in to this.
[EDIT]: additional question....do you play online games mostly, or are the dropped frames you are experiencing from installed games running off your hard drive?
Edited by ranchhand_, 08 March 2017 - 10:52 AM.