Build-Your-Own Computer Part 7: The Hard Drive

Buying a new computer can be an expensive ordeal. When you go to a big box retailer or manufacturer, you often pay for components you don’t need or get overcharged for the ones you do. The best solution is to build your own computer. What most people don’t realize is it’s actually surprisingly easy to do. To help you design your next computer, or just to become familiar with what to look for, WorldStart is doing a 10-part series on the components you’ll need to build your own computer.

In each part, I’ll offer recommendations on the components discussed. I’ll recommend parts to accommodate those both looking for value and those looking for high performance. Since manufacturers are always updating styles and features, your final decision should be based on your own judgment, aided by the knowledge you gain from these articles. You know what you want from your PC, I’m here to help you design it.

Part Seven: The Hard Drive

The hard drive seems like a simple choice, you pick how much storage you want and your done but there is quite a bit more to know. Hard drive technology has evolved over the last decade and there are quite a few options to consider. To understand the offerings you need to understand the technical terms defined below.

Type: Hard drives come in three different types: Magnetic, Solid State and Hybrid.

  • Magnetic drives are traditional spinning hard drives. They offer largest capacity, but have the slowest speeds and cost the least per gigabyte.
  • Solid State drives use electronic memory cells instead of a spinning disk to store information. They offer the fastest speeds, but cost the most per gigabyte.
  • Hybrid drives use principally a magnetic disk that spins, but they integrate a small portion of solid-state memory for programs and files you commonly access. They offer speeds faster than magnetic drives in many situations, but with far larger storage capacities for the dollar than solid state drives.

Interface: All modern desktop and laptop hard drives use the SATA (Serial ATA) interface. This interface began with SATA I, but modern motherboards now come with SATA II and SATA III interface ports. While these ports all appear identical the speed of information transfer differs greatly.  

  • SATA I: 1.5 Gbps ( ~150 megabytes per second maximum)
  • SATA II: 3.0 Gbps (~300 megabytes per second maximum)
  • SATA III: 6.0 Gbps (~600 megabytes per second maximum) 

Match up your hard drives interface with at least the same or higher revision of SATA port. Example: SATA II drive should be plugged into a SATA II or SATA III port while a SATA III drive should only be used in a SATA III port not a SATA II port for optimal performance.

Form Factor: The form factor has to do with the physical length of the drive. Desktop computers will have slots designed to hold 3.5″ hard drives. Most solid state drives come in 2.5″ form factor which can be fit into both desktop computers with a 3.5″ hard drive adapter (though some cases have 2.5″ slots now) and laptop computers. Some ultra-portable laptops require a 1.8″ form factor.

Spin Speed / Transfer Speed: On mechanical hard drives and hybrid drives, you’ll see a spin speed listed in RPM’s. The faster the spin speed, the faster (in general) the information can be found and transferred off the hard drive. 10,000 RPM is the fastest, followed by 7,200 RPM followed by 5900/5400 RPM drives. Solid State drives will list a maximum read and write speed. This is the easiest way to compare performance from drive to drive, as most SSD’s use standardized testing to list maximum transfer speed.

Cache: The cache on a magnetic or hybrid drive is used to buffer information in order to enable quicker transfer. In general, the larger the cache the better the performance of the drive. SSD’s since they read information very quickly, will not use cache but will contain some RAM to facilitate transferring and operation of the SSD controller.

Capacity: On all modern hard drives capacity will be measured in gigabytes (GB) or terabytes (TB). A terabyte is 1,000 gigabytes and a gigabyte is 1,000 megabytes. This can seen a bit deceptive; once you install the drive and see a lower than advertised capacity. Since manufacturers define a terabyte as 1,000,000,000,000 bytes, but operating systems recognize a terabyte as 1024 gigabytes and a gigabyte as 1024 megabytes, the actual available space on a 1 terabyte drive is 931 gigabytes.

My Recommendations

In this case since there are three different types of hard drives, I’m going to recommend one of each type. The budget recommendation will be the magnetic drive, the best value for the dollar will be the hybrid drive and the best performance will be the sold state drive.

Magnetic Drive – Western Digital WD Black 1 TB WD1002FAEX – $89.99


The Western Digital black edition features 1 TB of disk space on a 7200 RPM magnetic drive. The drive features 64 MB of cache and comes with an industry-leading five-year warranty. In terms of performance and warranty for a magnetic drive, this is hard to beat. If you need more storage, the black line comes in 2 TB and 4 TB models.

Hybrid Drive – Seagate ST1000DX001 1TB – $99.99


The Seagate hybrid drive combines 1 TB of magnetic storage with 8 GB of solid state space. The magnetic side of this drives spins at 7200 RPM and has 64 MB of cache, but the real special trick comes in with the solid state space. The hard drive’s processor automatically transfers the most accessed files on your hard drive to the 8 GB of solid state space, making frequently-used programs and files load very quickly. This process is completely automatic and invisible, but results in much faster boot-up times and significant improvements to program load time. Seagate backs this drive with a three-year warranty.

Solid State Drive – SAMSUNG 840 Pro Series MZ-7PD256BW – 256 GB – $229.99

The Samsung 840 Pro is one of the fastest solid state drives currently available on the market. Featuring 256 GB of space and a five-year warranty, you’re going to be happy for a long time. Since most people can’t store everything they have on 256 GB, it’s a good idea to use this drive as your boot drive and keep data files (pictures, videos, documents) on a secondary magnetic drive. My recommendation be a 4 TB Western Digital black series drive for a storage drive.


Click here for more articles in this series.

3 thoughts on “Build-Your-Own Computer Part 7: The Hard Drive

  1. Steve,
    I purchased a Samsung 840 solid state (not pro) but now I find out I can’t change the bios to configure from ide to ahci…any help would be appreciated.

    1. If you can’t change the sata chip type it has nothing to do with your hard drive but your motherboard. Newer laptop drives have it built in to prevent that as well as some desktops.

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