PCI-Express: why it is better

PCI Express or PCIe is an expansion card standard that was designed to replace the older AGP, PCI and PCIx bus standards. The PCI-Express standard offers higher system bus throughput and has lower I/O pin count.

PCIe has serial links between devices called Lanes, unlike the parallel connections present in PCI buses. PCIe can be a x1, x4, x8 or x16 type where the number equals the number of lanes. ( D,E : ports and sockets of a motherboard )

The PCIe (common revision 2.1) has a bandwidth of 16 Gbps for a 16 lane link (x16).

PCIe slot can be used for placing expansion port card, modems or sound cards, etc. But, Graphics performance can benefit the most with the use of PCIe because they require the maximum bandwidth for transfers. So, the graphic cards (or GPU) are built for and placed in PCIe slots.

PCI: Peripheral Component Interconnect

The PCI refers to the computer bus for attaching hardware devices in a computer. These devices can take either the form of an integrated circuit fitted onto the motherboard itself, called a planar device in the PCI specification, or an expansion card that fits into a PCI slot. ( A,B : ports and sockets of a motherboard )

Typically, PCI cards used in the expansion slots of a PC include network cards, sound cards, modems, extra ports such as USB or SATA, TV tuner and disk controllers.

The common specifications of PCI ports are:

• 32 or 64 bit bus-width
• 33.33 or 66.67 MHz synchronous clock
• transfer rate of 133 MB/s for 32-bit
• 32- or 64-bit memory address space (4 GB or 16 EB)
• 5-volt signaling

Motherboard: ports and sockets

This image shows only those interfaces (ports and sockets) that are important to our interest and point of view.

The rest of the small semiconductor parts of the motherboard are not of our interest, but for their designer.

In this post, only the names of all the interfaces have been mentioned.

Other than these interfaces, there are numerous chips and IC's for various functions as well.

They along with the functions of these interfaces would be described sometime later.

The components are so named:

A,B : PCI connector

C : CMOS battery

D : PCI-E (x1) connector

E : PCI-E (x16) connector

F : S/PDIF connector

G : Back-panel for I/O devices

H : 12V processor power (4-pin)

I : Rear chassis fan header (3-pin)

J : Processor socket

K : Processor fan header (4-pin)

L,M : RAM (channel A,B) sockets

N : Chassis intrusion header

O : Serial port header

P : Floppy Drive connector

Q : Main power connector (24-pin)

R : Parallel ATA (IDE) connector

S : Serial ATA (SATA) connectors

T : Front panel header

U : Alternate front panel power LED header

V : BIOS configuration jumper

W : Front USB headers

X : Speaker

Y : Front chassis fan header (3-pin)

Z : Front panel audio header

Motherboard : graphically revisited

In the post meant for the introduction of the Motherboard, we discussed it is called so because it is the backbone of all the components of a computer system. One of the most important point for assembling a computer is the knowledge is to know all the ports of the Motherboard.

This post is only dedicated to studying the placement of various

chips and ports present on the Motherboard with the help of good hi-def images..

In the next post, I'll write in detail about the ports of a Motherboard.