Windows is horribly bad at gauging the actual speed of hard drives.
It says 99% when in reality it is only reading/writing a few MB/s.
Run CrystalDiskMark and see how fast your drive really is.
I thnk its more when you tranfer a file the HDD gives it its most to do it as fast as possible, thus giving it his 100%
Or windows is just stuff, It also gives me 100% all the time
Also sleeve or rifle cooler? Wich is the quietest?