Seagate's Exos X20 is built on a standard 3.5in format but with an increased thickness of 26.11mm which together with Helium technology allows Seagate to use ten platters and 20 heads in the enclosure. Each 2TB CMR platter has an areal density of 1,146Gb/in². The drive has a spindle speed of 7,200rpm and there is 256MB of cache.
The Exos X20 uses TDMR (Two-Dimensional Magnetic Recording) technology. TDMR uses two read elements in the drive head to improve tracking accuracy which is vital as tracks are getting ever narrower as the areal density of platters increases. As the density increases the bit size gets smaller which in turn reduces the margin of error and increases the likely need for ECC to correct any errors.
The drive also employs a top cover attached (TCA) motor which helps reduce the effects of rotational and linear vibrations in rack/cabinets and in turn helps with improving the drive's performance.