I have a Samsung 850 Pro SSD, with Windows 8.1 installed to it. I have 20% of my hard drive over provisioned, because according to an article that's the sweet spot. How much additional space should I keep free on the drive so the speed of Windows isn't hindered? Meaning...how much can I fill it up besides the 20% I have set aside so Windows operations aren't significantly hindered? Is 5% set aside from Windows okay?