Hardware Reference
In-Depth Information
new systems. DDR4 is expected in systems in the 2013-2014 period.
See the Chapter 6 section, “ DDR SDRAM ,” p. 338 .
Current motherboards use memory in single-, dual-, or tri-channel modes. In single-channel mode,
each 64-bit wide DIMM is accessed individually, whereas in dual- or tri-channel mode, the modules
are accessed in multiples of 2 or 3 for higher performance. If you want to take advantage of the faster
multichannel modes, make sure you purchase and install memory modules in matched multiples.
Some memory modules are available with an extra error check bit for each 8 bits. These are called
ECC (error-correcting code) modules. ECC support is normally found only in server-type processors
and motherboards and is rarely found in standard PCs. If you want to install the more expensive ECC
modules in your system, make sure that your processor and motherboard provide the necessary
support.
See the Chapter 6 section, “ Parity and ECC ,” p. 357 .
For more information on PC memory of all types, refer to Chapter 6 .
I/O Ports
Virtually all motherboards today have built-in I/O ports. In rare cases where these ports are not built
in, they must be supplied via a plug-in expansion board that, unfortunately, wastes an expansion slot.
The following ports might be included in any new system you assemble:
• PS/2 keyboard port (mini-DIN type)
• PS/2 mouse port (mini-DIN type); some systems include a single PS/2 port usable by a
keyboard or mouse; use an adapter to permit a PS/2 keyboard and mouse to be connected to a
single port.
• Four or more USB 2.0 ports
• Two or more USB 3.0 ports (also compatible with USB 1.1, USB 2.0 devices)
• One or more FireWire ports
• One or more analog Video Graphics Array (VGA), Digital Visual Interface (DVI), High-
Definition Multimedia Interface (HDMI), or DisplayPort video connectors (integrated video)
• RJ-45 port for 10/100 or Gigabit Ethernet
• Analog audio connectors (speakers, microphone, and so on)
• Digital audio connectors (coaxial and/or optical SPDIF, HDMI)
• Two or more serial ATA (SATA) ports
• One or more eSATA ports
Note
Most motherboards feature SATA 6Gbps ports. On systems with two speeds of SATA ports
(6Gbps and 3Gbps), these ports are usually indicated with different-colored plastic headers.
Most recent motherboards lack the serial, parallel, keyboard, and mouse ports (referred to as legacy
ports ), instead relying on USB for those connections. You might want to avoid “legacy-free”
motherboards if you still use peripherals with those types of connections. Most motherboards feature
integrated sound, and many have optional integrated video.
 
 
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