Western Digital has several colors representing their performance and optimal use of their drives. Let's take a look at them today.
BLUE:
RED:
Red is the Server/NAS/datacenter HDD. This means they are optimized for 24/7 operation next to other vibrating, spinning drives. Most normal HDDs would eventually be damaged by the spinning of the hardware but these drives are designed so that they do not break from being near other HDDs. These drives have fast read speeds. They are also equipped with NASware 3.0 which optimizes them for servers. These drives support TLER.
BLACK:
Black is their elite lineup of HDDs. These have very high performance and large storage. They are optimized for gaming setups with very fast read-write speeds. They also have vibration control but not as good as the Red. This drive has a platter balancer that allows for better performance. This drive also has Error Checking chips in it that help cope with power cuts, and corrupted files. The seeking heads never touch the platters as well which makes it quieter than the blues and greens. It also has a Dynamic Cache, which means that it reduces congestion between reads and writes.
PURPLE:
Purple is the lesser-known one. These hard drives are optimized for surveillance/security systems. Since they are constantly recording and storing footage, they have high write speeds, instead of reading speeds like the Red. Supports TLER just like the Red and Red Pro. The Purple also has a special feature called All frame which is supposed to optimize it for ATA streaming to give you better connection and quality of your security stream. Intelliseek is also included which is supposed to reduce the amount of power it takes to seek through video. This drive also has the Blacks Dynamic Cable interface.
GREEN:
Green hard drives are for the person who wants cool, quiet, and somewhat crappy performance. These drives have less power draw and slower read and write speeds from the blues and blacks, but they are much cheaper. These drives have a large failure rate so don’t get these drives unless you really need them.
This is a reference Blog