Gone are the days when size and RPM were the two main factors in hard drives - with today's technologies expanding across many platforms Hard Drive manufactures have started to specialize their hard drive offerings into the class of drives by putting their intended uses into color classes. Here are a few of the more popular color classes and what their intended purpose is.
Green and Blue class hard drives are desktop drives: Desktop hard drives are found in you guessed it you home PCs or laptops. These drives provide reasonable performance to price ratio. The life expectancy depends on many factors such as environment, hourly use, and primary applications being used. Most desktop PCs do not run 24x7 so it is not unreasonable the hard drive will last as long as the PC does.
Black Drives Same as above - except on steroids. Black Drives are optimized across the board for higher-end PCs. They feature fast sustainable read and write speeds with a larger cache.
Purple Drives: Purple Drives are found in video surveillance systems that run 24x7 with a constant flow of video writes and reads. These drives are intended for higher speed writes with error correction to ensure the video is saved without problems, These drives feature a technology called AllFrame that minimizes errors in saving videos.
Red Drives: Red Drives are suitable for general use in Network Access Storage aka NAS, Red Drives are known for higher speed reads vs writes wich makes sense in a network environment when multiple clients are accessing data at the same time. Some Red Drives employ vibration sensors to reduce any sector errors when multiple Red Drives are running or the NAS is subject to vibrations.
Gold Drives: Normally found in data centers and are renowned for their overall performance and durability but come at a significant cost over other hard drives. Usually, Enterprise Drives come with an extended warranty and data recovery options from the manufacture. you are paying extra for performance, and assurance.
Regardless of Hard Drive Color always check with the hardware manufacture for the best solution for your needs. If you are setting up a Synology NAS, Synology has a great compatibility chart for which hard drives work for each Synology NAS. NOT all hard drives marked as NAS are compatible with every NAS. - > Links Below for manufacture recommendations
Final Thoughts: Solid State Drives SDD or now the newer standard NVMe drives. SDDs have surpassed the traditional hard drives and NVMe has surpassed SDD in all ways except Price but that too is quickly changing. A 6TB traditional Hard Drive is around $110.00 vs $700.00 + for a 5TB SDD. The point of this paragraph is to check the pricing of SDDs before buying a traditional hard drive.