Frequently Asked Questions About 2.5-Inch Hard Drives

If the hard drive in your laptop is broken or if you need to add more storage space, then you will likely need a 2.5-inch drive. The 2.5-inch form factor is specifically designed to fit inside of a laptop. Choosing a new hard drive can be difficult, but eBay makes the process easy.

How do you choose the right hard drive?

The choice of useful hard drive largely comes down to how much data you want to store. A typical hard drive may only have 1TB of storage space whereas others can go much higher. If you're looking for a fast drive, then you should pay attention to the speed of the interface and the rotational speed. The speed of the interface is measured in gigabits per second, but the rotational speed is measured in terms of RPM, or revolutions per minute. A faster rotational speed will result in less delay between the time it attempts to access data and the time the data is available for transfer. 4,800 RPM, 5,400 RPM, and 7,200 RPM are the most common rotational speeds. Another important factor is whether the drive is internal or external. An internal drive will provide a long-term storage solution whereas an external drive can be moved easily between computers.

What do the different types of interfaces mean?

The bus interface determines how the hard drive connects with the motherboard. There are multiple types of bus interfaces that allow for several different kinds of configurations in your computer. Types of interfaces on new and used hard disk drives include:

  • SATA: SATA is the most common type of commercial interface. There are several different versions of SATA, ranging from version 1.0 to version 3.3. Every subsequent version has a higher data transfer rate, but they are otherwise compatible with one another. SATA also has mini and micro variants as well.
  • eSATA: This is a variation of SATA that has an external rather than an internal interface.
  • PATA: PATA was a common interface in computers from the 1990s and early 2000s before it was superseded by SATA. If you're using an older computer, then it may still have a PATA drive.
  • SAS: SAS is primarily designed for servers and high-end computers. There are four versions of SAS, each with different data rates. The fastest version, SAS-4, has a bandwidth of 22.5 gigabits per second. SAS is also compatible with SATA 2.0 or later.
  • USB: USB is the most common means of connecting an external hard drive.
What is the memory cache?

The cache is a small amount of memory embedded on the drive. The computer will automatically allocate a certain amount of data to the cache, which is generally faster than the hard disk. Therefore, any data accessed from the cache rather than the hard disk will speed up operations slightly.