SATA II Internal Hard Disk Drives 2TB Storage Capacity

How to Choose SATA II Internal Hard Drives

While it's easy enough to choose your storage capacity when buying a laptop, it can involve a bit more work when you're trying to see how many TB you can put in your home-built desktop. Regardless of the drive, many people can find as many TB of data as they have room to store.

How Do You Know if it Fits?

The first thing to remember with any computer upgrade is that nothing else matters if the component doesn't fit. For a SATA II HDD that not only means that your machine has to support the SATA interface, but also that it has to physically fit in the drive bay. Most TB class drives come in one of two size categories:

• 3.5-inch: Originally developed for desktop use, these drives are physically larger in all dimensions, not just width. The advantage of the increased size is that it's easier to provide more capacity. The disadvantage is that they don't fit in laptop computers.
• 2.5-inch: While originally designed for laptops, these smaller disk drives also appear in some desktops. The advantage here is that you can always put one in a 3.5-inch bay if you have the right adapter, but the reverse option doesn't work.

What Determines Drive Performance?

Desktop hard drive performance depends on a number of things, and it's not always based on capacity. A 500 GB drive with the same size platters isn't necessarily any faster or slower than a 2 TB drive on the same interface because capacity isn't the only factor involved. In fact, there are a number of other factors that have a greater impact.

• Interface: One major factor is the speed of the interface, as a slower interface places a hard cap on the maximum data transfer rate. For SATA II, that's 3 Gbps, or roughly 300 MB/sec.
• Rotational Velocity: The faster the platters spin, the more data moves under the heads. This is one area where 3.5-inch drives have an advantage over 2.5-inch drives because the edge velocity is higher for a given RPM.
• Cache: Most rotating drives have an onboard buffer, or cache. This high-speed memory stores rapidly accessed data, anywhere from 8 MB to 256 MB. A bigger buffer means a more responsive drive.

Choosing a Drive

After compatibility, one of the main factors to consider is capacity. A 2 TB drive not only offers more space than a smaller one but can also maintain performance longer. Drive performance is always better near the outer edges of the disk, so computers use that part of the HDD first. One result is that a 500 GB drive with 400 GB of data will have to access much slower parts of the platter than a 2 TB drive with the same amount of data.