Hard Drives

Hard drives are the central storage device for data on your computer. On it rests the documents you create, the music you listen to, the games you play and the video you view. You'll want to choose a drive which is optimized for your primary purpose.
There are a few main things to consider when selecting a hard drive: internal or external hard drive, connection type, speed and capacity. Whether you call it a Hard Drive, a Hard Disk, or an HDD, budget permitting, always go for the fastest drive you can. Speed of data access is measured using RPMs (revolutions per minute). Typical drives range from 5400 to 7200 ROM, with more and more 9600 RPM drive appearing on the scene. A faster rotational speed means greater performance, especially in games, but may cause greater heat and noise.
The capacity, measured in GB (gigabytes), should depend on your own storage requirements. A higher capacity drive will invariably cost more than a smaller drive, so a balance must usually be struck between capacity and cost.
The hard drive interface, whether it's IDE, SATA, or SCSI determine a drive's application: IDE and SATA for personal storage and SCSI for enterprise and mission critical storage. Please see our Internal Hard Drive Buying Guide for more information.

ATA/IDE

Whether you call it "Advanced Technology Attachment" or "Integrated Drive Electronics", the name given to it by Western Digital, this connection method has the drive controller integrated into the drive, rather than connected to the motherboard. They can communicate at up to 133 MB/s.

SATA 1.5 Gbit/s

First-generation SATA interfaces, also known as SATA/150 or unofficially as SATA 1, communicate at a rate of 150MB/s or 1.5 Gbit/s.

SATA 3.0 Gbit/s

Soon after SATA 1.5 Gbit/s introduction a number of shortcomings were observed. This feature, Native Command Queuing (NCQ), was adopted as an optional supported feature for SATA 1.5 Gbit/s and SATA 3.0 Gbit/s devices.
SATA 3.0 Gbit/s is designed to fall back to SATA 1.5 Gbit/s when in communication with these older devices. In practice, some older SATA controllers do not properly implement SATA speed negotiation. SATA cables are less expensive and more compact than for ATA.
With the introduction of SATA, convention ATA is sometimes called Parallel ATA (PATA), which refers to the method in which the data travels over the wires.

Cables and Connectors for SATA Devices

Connectors and Cables are the same for either generation. They are used on 3.5-in SATA hard disks for desktop and server computers and 2.5-in disks for laptop or small computers.

SCSI (Small Computer System Interface)

Actually a variety of interfaces ranging from Narrow SCSI at 40Mb/s to Ultra-640 SCSI at 5120Mb/s may be substantially more expensive than other connections, but it offers a wider range of connection and device possibilities. Frequently SCSI connections may be found in higher-speed disks, up to 15000 RPM.