i really just want to know what might be causing the issue rather than anything else, it's not a problem at the moment as the drive is only used for video's and such, so speed isnt that essential.
the problem is the 3rd drive i have, a Samsung F3 2TB drive, it's been this way for a long time, i think since i got it, all the drives (except the seagate) are about 2 or more years old.
all 3 internal drives are connected through the same Sata controller
Motherboard: Gigabyte GA-EX58-UD5
the Internal drives are connected to the SATA 3Gb/s connectors.
this is the results of benchmarking:
Samsung F3 S.M.A.R.T information
Seagate Expansion drive (this one's through USB 3.0