Buying a powerful Power Supply

Since the PSU's or the Power Supply Units supply power to all of the components of the computer. It is extremely essential that one buys a PSU that provides enough power so as to provide enough power to the components that they do not slow down because of lack of power.
But buying a huge power supply does not mean buying a 2000 Watt SMPS. Doing that will take your electricity bill up to twice the normal. You need to buy a power supply that has a good amount of power while not having an excess of it.
Well, for starters you can be safe with a power supply of 300 Watts to the motherboard, a 20 Watt supply per drive, and a 20 Watt supply per 1 GB of RAM. That all works if you have a really low-end graphics card that doesn't require any more than 150 Watts to run and does not require any special connector to be powered.

• But in case your system has a high-end GPU, you'll have to add the required power of the GPU to  the above wattage and then buy the PSU. Also don't forget to check if the GPU requires an extra cable for power. If yes, add it to the required specifications for the PSU.
• Next, look for a power supply unit having a good amount of connectors of all types i.e. SATA, molex and PCI-E. Its always beneficial to buy one that has one or two connectors of SATA and molex for future expansions.
• And obviously, the PSU you are buying should have a large 60 mm fan, if not 120 mm one for excellent cooling performance for your system. My recommendation: Buy one with 120 mm fan even if it costs an additional $10.

Specifications of an Optical Drive

Various types of optical drives are available in the market. These include CD readers, CD writers, DVD readers, DVD writers, DVD combos, BD readers, BD writers and BD combos.

The specifications of an Optical Drive drives to be considered are:

Supported Media Types: The optical drive must support a major part of available types of discs in the market. Examples are CD-ROM ,

DVD-R ,DVD-ROM ,CD-RW ,CD-R ,DVD-RAM ,DVD-RW ,DVD+R and DVD+RW. Note that CD drives do not support DVD's or BD's and DVD drives do not support BD's. Also, the supported media types are different for a drive's read and write capabilities.

Interface: The interface that an optical drive uses and the port that it will use to connect to the system. The interfaces have transfer speeds of their own. For example, a max. of 167 MBps for IDE, 600 MBps for SATA. But, the current technologies available for optical drives can only provide speeds that are lower than modern systems. So in case, both the ports are available in your system, the interface is not much of a specification.

Buffer Size: The optical drive buffer works in exactly the same manner as the cache of a hard drive It stores a fraction of frequently accessed data that can be accessed extremely fast. It helps the system to access data from the drive even if the processor is being utilized 100% by other processes for a fraction of a second. Usually 1 or 2 or 4 MB.

Read & Write Speeds: All optical drives have different read and write speeds and different read or write speeds for different types of media. For example, DVD drives have a speed of 16x, 20x, 24x (where x is 1.35 MBps) and CD drives have a speed of 32x, 48x, 52x (where x is 150 KBps). An optical drive will always write different types of media at different speeds (For example, a CD at 48x, a DVD at 16x and a re-writable DVD at 4x). 

Specifications of a Hard Disk

Hard Disks have a few performance specifications that a buyer must always know accurately before purchasing the hard disk. Better specs will obviously make the system perform faster. The specifications are:

• Capacity: The amount of data that the disk can store. Usually 100's of GB's or TB's.
• Cache: A small memory chip that stores a fraction of frequently accessed data that can be accessed extremely fast. Usually 8 or 16 or 32 or 64 MB.
• Spin Speed: The speed at which the hard disk platter rotates. Usually, 5400 or 7200 or 10000 rpm.
• Average Seek Time: The average time in which the R/W head can be positioned over the requested track for random read/write requests. Usually, ~8-10 ms.
• Average Latency: The average time for the disk to rotate the platter and position the correct sector under the R/W head. Usually, ~3-5 ms.
• Interface: The interface that the hard disk uses and the port that it will use to connect to the system. The interfaces also have transfer speeds of their own. For example, a max. of 167 MBps for IDE, 600 MBps for SATA.

Ports for storage devices

Computer systems have a variety of secondary storage devices, some essential and the others optional. Some of these include hard-disk drives, optical drives, tape drives, floppy drives, etc.

For the transfer of data to and fro from the devices controllers are required to control the ports for connecting the devices. For the ports already present in the motherboard, usually the controller is on-board the motherboard too. The ports for hard-disk drives and optical drives include:

Parallel ATA (PATA/IDE):

• 40 pin cable and port
• max cable length: 45cm
• max number of hard drives: 4 (only in some motherboards, 2 per cable)
• max transfer speed: 133 MB/s

Serial ATA (SATA):

• 7 pin cable and port
• max cable length: 1m
• max number of hard drives: 8 (till now, one per cable)
• max transfer speed: 150-600 MB/s

SATA ports are fast replacing PATA ports. Controllers for extra ports like additional SATA or PATA ports, SCSI, USB, etc. that have been added via PCI card or similar are built on the PCI card itself.

There are ports for additional storage expansion as well like USB and SCSI. SCSI is mainly used with servers that have large arrays of hard-disk drives whereas USB controller is already present on the motherboard. The latest USB 3.0 specification is supposed to achieve 600 MB/s.

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.