An internal hard drive is what allows your computer to store information, such as the data for programs, documents, photos and videos. Unlike the more recently invented solid-state drive (SSD), a traditional hard drive has a physical spinning disk, and the faster that disk can spin the faster the hard drive can generally read and write information. So, a hard drive with 7200 rpm (revolutions per minute) is often faster at storing and accessing information than a hard drive with 5400 rpm, however, the difference can be undetectable. More complex programs, like graphic design software or video editing, can benefit from a faster hard drive.

Storage capacity is another important deciding factor. How much do you need to store on your computer’s internal hard drive? If you intend to store a lot of videos or PC games, you may want to look at a 1TB hard drive or larger.

Finally, whether you are adding a second hard drive to a desktop computer or building a gaming PC from scratch, you will have to consider your hard drive’s form factor—size and shape—to determine compatibility with the other components of your computer.

Internal hard drives are necessary for storing your computer’s essential information as well as the data needed to run programs. This includes the basic programs your computer uses all the time and the programs that you choose to load onto your computer.

You can store a lot of other information—photos, documents, games—on external hard drives or external solid-state drives. These external drives have the benefit of being portable, allowing you to access the information on them from many devices. It is also a popular choice to use external computer drives to back up information from your computer in case it ever crashes.

How you use internal drives all depends on the programs you are running and the amount of data you are storing and accessing. It is advantageous to have extra space on any computer drive because drives that are full can run more slowly. It can also be beneficial to run a program on one drive while accessing files from another. That way, neither drive is handling the full workload. Whatever size and speed you choose for your computer drives, ensure that you protect your information from viruses by installing antivirus and security software on your devices.