Hardware Reference
In-Depth Information
cable and port connectors are shown in
Figure 7.13
.
Figure 7.13. eSATA (left) and standard internal SATA (right) cable and port connectors
compared.
eSATA supports all SATA transfer speeds up to 6Gbps rate (600MBps); however, some are limited
to 3Gbps (300MBps) or less. Even at 300MBps, eSATA is significantly faster than other popular
external interfaces such as 1394a/FireWire 400 (50MBps) and USB 2.0 (60MBps). In fact, with
300MBps or 600MBps of bandwidth, eSATA is three to six times faster than 1394b/FireWire 800
(100MBps), and even the 3Gbps (300MBps) mode of eSATA is faster than USB 3.0 (5Gbps or
500MBps). How can 300MBps eSATA be faster than 500GBps USB 3.0? One reason is that there is
a large amount of overhead in the USB specification to allow for even longer cable lengths (5 meters
or 16 ft.), which drops the actual data throughput to well under 400MBps, but the other reality is that
any external drive connected via USB 3.0 consists of a SATA drive plus circuitry converting the data
from SATA to USB 3.0 inside the enclosure, thereby reducing efficiency even more. When using
eSATA, there is no signal conversion inside the external enclosure (eSATA is SATA, after all)
making the interface much more efficient. In short, eSATA is just about the ideal connection for
external drives, allowing them to work just as if they were internal to the system.
If your system doesn't have an eSATA port built in, you can easily add one using a very inexpensive
cable and bracket assembly. The cable will plug into one of your motherboard-based SATA ports,
and the other end of the cable will be an eSATA connector mounted in an expansion card bracket (see
Figure 7.14
). Brackets are available with one or two ports as necessary.
