HD Tune's benchmark looks OK.
Is
The 15% Rule of Thumb for Mechanical Hard Drives true...?
Because after you said it is OK, I think for a while and did removed some contents from my HDD. Now it has at least 15% free storage (272GB free from 1810GB). Before, it was almost full.
I don't actually know if it is working but I noticed better performance for example when I open my game folder (I put all game icon shortcuts in one folder, and I changed the icons into better resolution .ico, and viewed by large, making the folder looks aesthetic). Usually it takes longer time to load those icons. Some icons even shrink.
Also noticed a little bit smoothness in extracting rar files (Usually lag).
Edit:
New CrystalDisk Score.png