WD Hard Drive Interface Guide For Compatible Cable Connections Part II

Which external drive interface is the right choice: USB, FireWire, eSATA, or Gigabit Ethernet?

Each interface has its strengths, which are explained in detail below. The right choice depends on compatibility with your computer and how you want to use your device. First, look at the connections on your computer.

Wd Hard Drive Interface Guide


USB 2.0 is the industry standard peripheral connection for most Windows-based computers. This connection transfers data at a maximum rate of 480 Mb/s. Sustained data transfer rates, usually from 10 to 30 MB/s, vary depending on many factors including the type of device, data being transferred, and computer system speed. If your USB port is an earlier version, USB 1.0 or 1.1, you can use a USB 2.0 hard drive, but transfer rates default to the slowest version. If you don’t know the version of your computer’s USB ports, refer to your computer documentation or contact the manufacturer.


FireWire, also called IEEE 1394, is a high-performance connection standard for personal computers and consumer electronics. This interface uses a peer-to-peer architecture in which peripherals negotiate bus conflicts to determine which device can best control a data transfer. FireWire has two configurations:

  • FireWire 400, also called IEEE 1394a, transfers large amounts of data between computers and peripheral devices at rates up to 400 Mb/s. With higher bandwidth, longer distances, and a higher-powered bus, this interface is suitable for hard drives, digital video, professional audio, high-end digital still cameras, and home entertainment devices.
  • FireWire 800, also called IEEE 1394b, provides the highspeed connection and bandwidth required for multiple-stream, uncompressed digital video and noise-free, high-resolution digital audio. It offers maximum flexibility with long-distance cabling and configuration options not available with USB.


SATA is very effective for external storage applications, and the external SATA (eSATA) cable and connector application provides a physically secure and fast connection for external hard drives. With up to 3 Gb/s data transfers, this interface is suitable for hard drives, home networking, digital video, and home entertainment devices such as set-top boxes and personal video recorders. eSATA and internal SATA cables and connectors cannot be used interchangeably. This is an important feature since eSATA cables and connectors are designed for 5000 insertion and removal cycles while internal SATA cables and connectors are designed for only 50 insertion and removal cycles. To achieve eSATA connectivity with an external SATA drive, a SATA PCI card must be installed on the host computer.

Note: SATA cables with an L-shaped connector are incompatible with WD eSATA devices.

Gigabit Ethernet

Ethernet is a standard method of connecting computers to a local area network (LAN) using coaxial cable. As an external hard drive interface, it is most often used for network attached storage (NAS) applications in which files can be shared across a network.

Gigabit Ethernet, with its data transfer rate of 1000 Mb/s, is the latest and fastest Ethernet standard that evolved from the earlier Fast Ethernet (100 Mb/s) and Ethernet (10 Mb/s) standards. Benefits of Gigabit Ethernet include increased bandwidth, quality of service (QoS) features that promote smooth transmission of audio and video, and compatibility with existing Ethernet and Fast Ethernet networks.

USB 2.0 FireWire 400 FireWire 800 eSATA Gigabit Ethernet
Hot-swappable (attach a device without rebooting the system) Hot-swappable (attach a device without rebooting the system) Hot-swappable (attach a device without rebooting the system) Hot-swappable (attach a device without rebooting the system) Can attach a device to a system’s network adapter, router, switch, or hub port
480 Mb/s maximum burst transfer rate 400 Mb/s maximum sustained transter rate 800 Mb/s maximum sustained transfer rate; twice as fast as FireWire 400 Up to 3000 Mb/s maximum sustained transfer rate 1000 Mb/s maximum sustained transfer rate; ten times as fast as Fast Ethernet
Best for connecting to different systems quickly and easily Best for transferring large amounts of data frequently or for audio/video programs Best for multiple-stream digital video and high-resolution digital audio Best for transferring large amounts of data frequently or for audio/ video programs Best for sharing large amounts of data and/or large audio/video files across a network
More popular for PCs More popular for Macintosh® computers More popular for Macintosh computers More popular for PCs More popular for PCs

Note: For convenience and flexibility, choose a WD hard drive with both USB and FireWire interfaces
(available in dual and triple interface configurations) or with both USB and eSATA interfaces.