Western Digital has released a statement that states which drives make use of the SMR ( or shingled magnetic recording), which is slower when compared to its newer CMR technology. The company announced that the drives that use SMR technology range from WD Red HDD to WD Black HDDs. The other HDDs use the CMR recording technology that features a wider write head than a magnetic track. This means that the CMR technology has a guard space between the tracks to prevent it from overwriting adjacent tracks.
Western Digital released a statement showing which drives from their HDDs series use the slower SMR technology and which ones make use of the faster CMR technology
Drive series featuring SMR include the WD Red and WD Blue HDD series, both of which come in a 3.5" form factor. From the WD Red HDD series, the 2 TB HDD, the 3 TB HDD, the 4 TB HDD, and the 6 TB HDD while from the WD Blue HDD series, the 2 TB HDD and the 6 TB HDD.
The WD Blue and WD Black Series come in the 2.5" form factor. The WD Blue 2.5" HDD series that feature the SMR technology is the 1 TB drive, and the 2 TB drive while from the WD Black 2.5" HDD series only has a single drive that uses the SMR technology, which is the 1 TB drive. All other HDDs in these series use different recording technology called CMR or conventional magnetic recording.
|WD Red||WD Red Pro||WD Blue||WD Black||WD Purple|
|3.5″||1TB or below||CMR||CMR||CMR||CMR||CMR|
|2TB – 6TB||SMR||CMR||SMR / CMR||CMR||CMR|
|8TB and above||CMR||CMR||–||–||CMR|
|2.5″||500GB or below||–||–||CMR||CMR||–|
The difference between the CMR technology and the SMR technology is how they record the data onto the magnetic disk. The CMR technology features a wider write head when compared to the magnet track. This technology features a guard space between the tracks to prevent it from overwriting adjacent tracks. While the SMR technology doesn't have a guard space, instead, they overwrite adjacent tracks and then re-writes the tracks.
The main reason that Western Digital issued this statement is that the drives which utilize the SMR technology will be slower when compared to the drives which make use of the CMR technology.