SEAGATE ST4000DM00 4TB 5400RPM SATA 3.5 Hard Drive - Used, Tested OK !!!
This specific model is defined by its use of Shingled Magnetic Recording (SMR) technology. Buffer Size: --. 4 TB SATA Desktop 3.5 Hard Drive. Cache Size: 256 MB (a massive buffer required to mask the write performance penalties of SMR).