The hard drive is a trusty component used to store a lot of content on your PC. Available in sizes that can go all the way up to 16TB (that's 16,000GB), and different models are available from various vendors. Western Digital is one such company that offers both mechanical and solid-state drive (SSD) storage, but it can be a little confusing as to which one you should go with. Western Digital has the Blue, Black, Red, and Gold brands for mechanical drives.
It's always recommended that you go with an SSD for Windows 10 and other software to be installed on, leaving a mechanical drive free for storing games and files. The Western Digital Blue is the hard-disk drive (HDD) built for the desktop, while the Black takes things to the next level for professionals and gamers. Enterprise and server owners have the Gold series to look through and the Red series of drives are specifically designed for NAS use.
Here's a spec comparison of Western Digital drives.
|Category||WD Blue||WD Black||WD Red||WD Gold||WD Purple|
|Capacity||500GB to 6TB||500GB to 6TB||750GB to 10TB||1TB to 12TB||500GB to 10TB|
|Interface||SATA III||SATA III||SATA III||SATA III||SATA III|
|Data transfer||175MB/s (6 TB)||218MB/s (6TB)||178MB/s (8 TB)||200MB/s (12 TB)||210MB/s (10TB)|
|Cache||64MB||64MB to 256MB||16MB to 256MB||128MB to 256MB||64MB to 256MB|
|7,200 RPM||5,400 RPM||7,200 RPM||5,400 RPM|
|Use||Home||Work and gaming||NAS||Enterprise||Surveillance|
|Warranty||Two years||Five years||Three years||Five years||Three years|
|Price||From $43.99||From $63.99||From $62.99||From $79.99||From $53.49|
Pricing is fairly competitive between vendors and Western Digital's family of drives, thanks to the affordability of mechanical drives. You should go for the fastest drive with the most cache and capacity you can afford. This specification comparison should help you get started.
Updated March 20, 2018: Added the Purple family of Western Digital drives to our specifications comparison table.