Well because you've got your games on a separate drive, I'd be led to believe that could also be the problem, but it does sound like it's your OS' drive as that would also have an effect on your games. I think, if it's that much of a hindrance to your machine, you might be best off saving all of your documents (to a cloud or USB or something) and resetting your PC fully. And then reinstalling all of your stuff. I know this is a hassle, but if the problem is still there after doing this, it kinda finds the solution to your problem, which would probably be to load your OS onto a different drive, or buy a new drive as well. BUT FIRST BEFORE DOING ANY OF THIS, UPDATE YOUR SSD' DRIVERS! https://www.kingston.com/en/support/technical/category/ssd
Find which one is yours from here!