The 21st century has seen an explosion of digital data, as electronic devices of all kinds, ranging from camcorders, cameras, and laptop computers have found widespread use. Naturally, storage devices with large capacities, are a need of the day. Hard drives are the standard magnetic disks used in computers for data storage.
No matter how much space you start out with, eventually, you may run out of storage in the near future. Your aggregated store of photos, music, videos, and movies is only going to expand with time and you are going to reach a point where, buying extra storage is not an option but a necessity.
How are They Different?
Access Speed and Data Transfer Rate
Two factors which need to be compared are the access speeds and data transfer rates. The data transfer speed offered by internal drives with latest SATA interfaces, amounts to several megabytes per second. In terms of access speed, they no longer have an edge as the SATA interface speeds have been matched by eSATA and FireWire, used in portable drives.
With the introduction of eSATA interface in external drives, it indeed offer comparable data transfer speeds. The latest FireWire 800 based hard drives also offer up to 800 MBPS of data transfer speed. So, in terms of these two aspects related to data access, both internal and external drives are on par.
The advent of the USB 3.0 and USB 3.1 has made it possible to transfer data at a speed of nearly 5 GBPS and 10 GBPS respectively. Thunderbolt interface allows for data tranfer speed from 10 GBPS (Thunderbolt) to 80 GBPS (Thunderbolt 3). Its future versions will let you transfer data upto 100 Gigabytes in a second. Thus, Thunderbolt is fastest of them all.
Portability and Cost
The aspect where external hard drives win over internal ones is portability. For users who need to carry around their data or back it up regularly, external ones are the best choice. Opt for such a drive with high disk rotation speed and large memory cache size, which can provide you with high-speed performance.
With the USB and FireWire interfaces, you can easily plug and play an external drive on any computer, to access data. On the other hand, transferring from an internal one can be cumbersome. They definitely cost lesser than external drives. You have to pay an extra price for portability.
If you are looking for extra space at low cost, go for an internal drive, but if price is not an issue, go for an external one. If you are looking for portability and need to frequently transfer data between different machines or you need a data backup solution, again the portable drive is the best choice.
If you are looking for high data access speed and plan to use the drive as part of your gaming computer, it's best to go for the latest SATA disks.
One of the latest innovations which are fast leaving traditional electromechanical hard drives behind are solid-state drives, which are based on NAND flash memory. Though they are expensive compared to hard drives, they outperform the traditional drives in every department.