Components of a Computer

Posted by on Dec 26, 2013 in Instruction | 0 comments

Components of a Computer

The basic components of a Computer

Before you can really start to understand how to maximize the effectiveness of using your computer you would really benefit in understanding what the components of a computer consist of and how those pieces play nicely together. Whether you’re using a laptop a desktop or even one of the newer tablets, basically… they’re underlying components are very similar if not exactly the same.


Let’s start with the overview….

pc diagram image


Inside the computer case, you’ll find the following components.  Click on the each section to explore the roll they play in today’s PC.



Motherboard image

High-end motherboard by Gigabytes showing the connection ports, the RAM Memory card slots (green and pink) and the expansion card slots (blue, white and orange)

The Basics

The motherboard is is the foundation of all your other components. The motherboard provides a way for all your other components to communicate in addition to performing some functions of it’s own. The functions of a motherboard for a desktop PC and a laptop are relatively the same with a few minor exceptions which will be noted below.

Looking at the motherboard, you’ll see a rather large socket for the CPUCentral Processing Unit - typically but incorrectly - referred to as the brains of the computer. See below for more detailed information to plug into, at least 2 but up to as many as 6 long sockets for the RAMRandom Access Memory - see below for more info. memory chips to plug into, a number of slots for expansion cards and a whole slew of plugs for your peripherals to plug into such as your keyboard, mouse, monitor, speakers and so on.

The Advanced

The cost of a new motherboard can generally be tied to the functionality and capabilities it contains.  Motherboards come in different sizes – generally referred to as the “form factor.”  While the form factor is generally used to reference the size of the motherboard, it also includes the layout of the motherboard as well.  Pertaining to size, from large to small, the form factors are Standard-ATX, Micro-ATX, Mini-ATX, Nano-ATX and Pico-ATX.

motherboard form factor comparison image

Size comparisons of various form factors

Motherboard prices can range from a low of about $40 to a high of about $1,100 with the price mostly being based upon functionality and speed.  Some motherboards have built in video graphics chips for example while others do not.  Those that do have “on-board” graphic processors (GPUs), may allow for output using various video formats such as VGA, DVI, HDMI, S-Video and RCA.

video connectors image

Connector Types: 1-HDMI, 2-DVI, 3-Component, 4-S-Video, 5-Composite (RCA)

Ironically, those motherboards that do contain on-board video generally tend to be the lower priced ones.  Those without on-board video, require separate video cards which plug in to the motherboards.  Plug-in video cards run from a low of about $30 to a high of nearly $4,000.  Yes – you read that right…. $4,000 – but that’s a topic for a whole separate discussion.

The expansion slots on a mother board – the types and numbers – also have a bearing on the price. Typical expansion cards you can purchase to beef-up your PC would typically be video cards, sound cards, network cards and TV tuner cards.  Even if your motherboard already has on-board video capabilities, you can generally purchase a video card which when added would expand upon the current capabilities.  For example, although my motherboard has on-board video capabilities, I’ve added a video card which then allows me to hook up a second monitor. Likewise for sound capabilities.  Even though your motherboard may have a stereo sound jack connector, installing an audio card could give you 5.1 surround sound with optical laser output allowing you to connect your PC to your home audio system.  Unfortunately, because laptops are designed for compactness, you won’t find any expansion slots like a desktop motherboard.  Instead, you “might” find a small slot on the side of the laptop to slide a small expansion card in.  This small slot is referred to as a PC Card (originally PCMCIA Card for Personal Computer Memory Card International Association)

PC slot types image

Typical motherboard expansion slots: AGP, PCI, PCI Express X1 & x16

PC Card Image

The Laptops version of an expansion card


video expansion cards in motherboard image

Two video expansion cards installed into a motherboard and connected to aggregate their capabilities. Each video card has two DVI connectors thus allowing this computer to connect to 4 monitors at once.

The CPU type that the motherboard accepts will also have a bearing on the cost.  Motherboards designed to accept, and take advantage of, higher quality and speedier CPU chips will expectedly be more expensive.  The CPU mount – referred to as the CPU Socket – on a motherboard is designed specifically for a certain class of CPU.

CPU Socket image

Typical CPU Socket

A CPU manufactured by Intel, will not fit into a motherboard designed for an AMD CPU.  Likewise, a motherboard designed for an AMD Phenom CPU will not accept an AMD Sempron CPU.  As new CPUs are developed , new socket types are developed to handle them.  If you purchase a computer, knowing what type of CPU socket the motherboard has will tell you what kind of CPU chips you can consider buying should you wish to upgrade your PC at a later time.

There will typically be from 2 to 6 slots on the motherboard for mounting your memory chips (referred to as RAM chips – for Random Access Memory).  More often than not, these will be color coded – usually with different colors.  The reason for this is to indicate the various banks of memory that the computer is accessing.  As in this photo…

Motherboard RAM slots image

Motherboard RAM slots showing the two colors, blue and yellow, representing the two banks of memory controlled by the motherboard.

two slots are colored blue and two are yellow.  Each like-colored set of slots represents a bank of memory – in this case, bank 0 and bank 1.  As a rule of thumb – and in most cases a requirement – when installing memory chips, the same type of memory chips, in size and speed, must be installed in the same bank of memory slots. Please reference the RAM section for more detailed information.

Additional considerations when looking at motherboards are the boards speed and whether or not the board is made for 32 bit or 64 bit processors. The motherboard’s speed is generally referred to as the “Bus” speed. The “Bus is basically the circuitry that connects the various motherboard components. While there are numerous Buses on the motherboard – each operating at various speeds, the one most commonly referred to when quoting motherboard speed is the one connecting the CPU to the memory. This bus is referred to as the “front-side” Bus and the speed is quoted in megahertz (MHz): the faster the better.

motherboard bus layout diagram

a “typical” motherboard component layout showing the major components and the ‘Bus’ connections.

With respects to 32 bit versus 64 bit capability, think of this in terms of the width of the “highway” that the data runs around on the motherboard. a 64 lane highway, being twice as wide as a 32 lane highway allows for more data transfer at the same time.

Other factors affecting the performance, and thus price, of the motherboard would be the  additional on-board processors, manufacturer and warranty terms.


CPU Image

Front and back of a typical CPU. Note the number of tiny pins on the back of the CPU

OK… I’m going to take a little ‘heat’ here by my fellow Techies for over-simplifying this but a CPU is really just a whole lot of microscopic transistors which are really just on/off switches. When a program is executed, these switches get turned on or off and based on the combinations of on/off switches, program function is carried out.

By the way… the following information applies to desktop and laptop systems (actually, to pretty much anything – tablets, eReaders, etc)

When I bought my first computer back in the late 70’s, the computer had a CPU known as an 8088. That CPU contained 29,000 transistors. My current computer has an AMD Phenom II X6 1065T CPU which boasts a whopping 45 million transistors. Million – that’s right – Million! But… get this, that’s nowhere near what the top-end processors today have. Take the 10-core Xeon Westmere ex CPU with … drum roll please… 2,600,000,000! And just in case you get lost in all those zeros, that’s 2.6 Billion. That capability comes at a pretty cost though. Where my CPU ran a bit over $150, the Westmere ex runs a few Benjamins over $4,000.

Today’s CPU’s have a few ways of comparing them: by speed and cores. Today’s CPU’s are measured in terms of Gigahertz (GHz). Looking at my first computer again, that 8088 CPU was able to execute 500,000 instructions per second. Today’s Intel’s i7 Extreme Edition CPU delivers a whopping 177,730 Million instructions per second or… 177.7 Billion!

When looking at today’s CPUs you’ll also here the term ‘core’ thrown around a lot. Basically put, a 4-core CPU, is like having 4 independent CPU’s on one chip. While you won’t necessarily get 4 times the speed, you do gain about a 50% increase in performance for each additional core. Additionally, the cores can be run independently. While 2 cores may be dedicating themselves to one program the other two can be focused on a totally different program or function.

So… with different manufacturers, single or multiple cores, different speed CPUs, how does one really compare CPUs on a relatively even platform?  It’s hard.  Thankfully, though, there are organizations where one can go to find this information.  Generally, these organizations run the CPUs through a standard bank of tests testing everything from raw computing power to graphics handling.  One of these organizations, CPU Benchmark dot net, upon running various tests then assigns a benchmark score for each CPU and thus gives the consumer a reasonably reliable way of comparison shopping.

RAM Modules

More frequently know as “memory chips”, the Random Access Memory or “RAM” modules play a greater part in how well a computer operates than might first be thought.

When you run a program on your computer, the computer takes a copy of the program that is stored on your hard drive and places that copy into the RAM modules.  This is done because running the programs from your RAM memory modules is substantially faster than trying to run them directly from your hard drive.  This also saves wear and tear on your hard drive.  The computer not only does this for the programs you run but for your operating system and any documents, pictures, video clips, etc. as well. Once your computer boots up, virtually everything that is done from that point, is done from the RAM modules.  As you can imagine, that places quite a bit of demand on these relatively small components of your computer.

Ram Module samples image

Typical RAM module sizes / formats

These modules come in various sizes and speeds both of which need to be matched to your specific motherboard when replacing or upgrading them. RAM modules are referenced by the amount of memory they have and this is generally referred to in terms of Gigabytes.  One Gigabyte is one billion bytes of information storage.  When used n the context of a conversation, you might respond to a question as to how much RAM does your computer have with ….My computer came with 6 Gigabytes (GB) of RAM.

Your computer’s motherboard will generally dictate how much RAM it can support both in the number of modules in addition to the maximum amount of memory it can support.

For example,  this motherboard shown here contains only four slots for RAM modules – the longer red and yellow connectors in the bottom right hand portion of the picture.

Gigabyte motherboard image showing RAM slots

The RAM module connector slots are the long red and yellow connectors in the lower right hand section.

If you were to look at the specs for this motherboard, you would find that the maximum amount of RAM it can support is 16 GB.

One other major component which dictates the maximum amount of RAM your computer can take advantage of at any given point in time is the operating system.  The 32-bit version of Window’s 7, for example, can only address a maximum of 4 GB of RAM, whereas the 64-bit version would be able to address the full 16 GB that the motherboard can support.

When it comes to buying RAM, you’ll need to not only know how many modules your motherboard can handle and what the maximum amount of Gigabytes are that it can support combined with the maximum amount of RAM your operating system can utilize but also what the format of the module and the RAM speed that are supported are.

As mentioned a bit earlier… RAM modules come in various Formats and your motherboard will only take one of the many that are available.  The more common formats are SIMMs (Single Inline Memory Module), DIMMs (Dual Inline Memory Module) and SODIMMs (Small Outline-Dual Inline Memory Module).   In addition to the module format, there are different classes of memory: DDR, DDR2 & DDR3.  The “DDR” stands for “Double Data Rate” and relates to the speed at which the module processes the data.  To help make sure you use the correct module, most modules will have a small notch cut into the edge of the module which has the contact points.  Making sure the notch is in the correct position and matches up with the corresponding plastic “bump” in the slot is a good indicator that you have the correct module for your computer.

RAM Module size samples

Various RAM modules & sizes

DDR Ram Types01 Image

Typical RAM DDR Types

RAM Module Insertion image

RAM module insertion showing the alignment pin and corresponding module slot and the two end clips to secure the module


Finally… as if all that weren’t enough… there are additional considerations when it comes to buying RAM modules….

  • Buffered versus unbuffered
  • Error correcting coding or non-error correcting coding
  • CAS Latency values
  • RAM speed (400 megahertz (MHz) versus 533 versus 677 versus…..)
  • Air cooled versus v=fan cooled versus liquid cooled
  • and more…

The bottom line…..

When replacing or upgrading your RAM modules…

it’s best to consult with your motherboard manufacturer or in lieu of that with the PC manufacturer to determine what your best options are.  In lieu of that… either be prepared to do a good hour or more of research or… better yet… consult with a professional – like me!

Hard Drive

Important item one about hard drives…The hard drive of your computer is where all of your programs and data are stored.  Basically…. everything you care about… or, rather… should care about.

Important item number two about hard drives…… they will eventually fail.  Not “if”… but “when” they fail, you could and most likely will loose everything… programs….data… everything.

Sorry to start this little section on such a downer… but ignorance of the truth doesn’t postpone the inevitable.  The fact is, your hard drive is a mechanical device meaning that it has moving parts and moving parts eventually wear out.  Now, they may not wear out and break down for years… but, then again, like all mechanical devices, they can also malfunction prematurely.  Backblaze, an online data backup company which keeps approx. 25,000 hard drives in use at any given time has found that approx. 5 out of a hundred hard drives will fail within the first year and a half.  Of the remaining, one or two out of a hundred will fail within the next year and a half and of those that make it past 3 years, another 12 out of a hundred will fail within the next year:

table of 4 year hard drive failure rates

Typical hard drive failure rates over 4 years

Let’s look at what makes up a hard drive:

image of a Standard Desktop PC Hard Drive

Standard Desktop PC Hard Drive

internal image of a hard drive showing the major components.

Hard drive cover removed shows the major components: Actuator, actuator arm and head and the platters.

A closeup image of the actuator arm and head and the hard drive platters.

A closeup of the actuator arm and head and the hard drive platters.

Inside the hard drive case, you’ll find a number of disks, referred to as platters.  Each platter has a read-write head which floats above the platter and reads data from and writes data to the hard drive.  The more data the hard drive holds, the more platters it will have.  The typical hard drive in today’s computers will have 4 or 6 platters and with each platter having two read/write heads (one for each side of the platter) and that would mean a total of 8 to 12 heads. The platters in the hard drive spin at about 5,400 rpms (revolutions per minute) with high speed hard drives running at about 7,200 rpms and some “top-end” drives running at 10,000 rpms.  As the platters spin, the read/write heads (actually, known as actuators), zip back and forth over the platters to read and write the data. The faster the speed of the hard drive, the faster the data can be read from or written to the hard drive.

As previously mentioned, the capacity of the hard drive depends on the number of platters and how they are formatted (among other things).  Here’s how common hard drive ‘size’ references stack up:

The common prefixes are as follows:

  • Kilobyte (KB) = 1,024 Bytes
  • MegaByte (MB) = 1,024 Kilobytes or 1,048,576 Bytes
  • Gigabyte (GB) = 1,024 Megabytes or 1,073,741,824 Bytes
  • Terabyte (TB) = 1,024 Gigabytes or 1,099,511,627,776 Bytes

The typical hard drive in a desktop computer sold today will between 500 GB (Gigabyte) to 1 TB (Terabyte).  This chart gives an idea of how much data can be stored on a hard drive based upon it’s “size” (keeping in mind that these figures are  loosely based on averages and depend on things such as the quality of the pictures, the lengths of the songs and videos etc:

What can you store?

Capacity Digital Music (Hours) Digital Photos (Files) Digital Videos (Hours) DVD Quality (Movies) HD Videos (Hours)
320 GB up to 5,000 up to 100,000 up to 320 up to 80 up to 80
750 GB up to 12,000 up to 240,000 up to 750 up to 180 up to 180
1.0 TB up to 16,600 up to 320,000 up to 1,000 up to 250 up to 250
2.0 TB up to 33,320 up to 640,000 up to 1,000 up to 500 up to 500
3.0 TB up to 49,980 up to 960,000 up to 3,000 up to 750 up to 750


As all technology is under constant improvement, hard drives are no different.  Newer hard drives are turning towards all solid state (SSD) technology, replacing the platters and actuators with memory chips.  No moving parts means no parts to wear out and less heat buildup.  BUT…. ahhhh… there had to be a ‘but’ didn’t there?  Just because they’re solid state, doesn’t mean that they don’t wear out.  In actuality, SSD hard drives tend to have about the same life-span as the traditional hard drive.  So why bother then?  SSD drives are faster than the typical hard drive with respects to how fast they can read and write the data. A program that may take a few seconds to load from a typical hard drive may load in the blink of an eye with an SSD. Additionally, since there are no moving parts, they tend to run cooler and – of course – a lot quieter.  Unfortunately..being newer technology, they are still on the expensive side.  Where $80 will buy you a 1TB standard hard drive, the same amount of money will maybe fetch you a 120GB SSD.  An alternate option would be a hybrid hard drive which would combine the best of both worlds combining some SSD technology into a standard hard drive.  with this SSD hybrid drive, you’d have about 4 or 5 GB of solid state memory which would run your operating system with the remaining 500 GB of standard hard drive action for your data – and for about $80 or $90.

internal image of a Solid State Hybrid Hard Drive

Solid State Hybrid hard drive

image of a Solid State HD

Solid State Hard Drive

Hard Drive Connectors:

While virtually all of the newer computers use the newer SATA format connectors, if you’re planning on replacing the hard drive on an older computer, you may find the hard drive has the older IDE PATA format connector.  Of course, there are adapter cables which can be used to allow you to use the hard drive of your choice but adapting the newer, faster SATA hard drive to connect to an IDE connector on an older motherboard will hinder the newer drive’s performance.  It merits to check the motherboard as many of the motherboards have both formats of connectors.

image of SATA and IDE/PATA hard drive connectors

The different types of hard drive connectors

Image of SATA and IDE connectors

Comparision of SATA connectors (left) and an IDE (PATA) connector (right) on the motherboard

The last thing about hard drives – a repeat of the first… they will eventually fail so always have a backup of your data.  Any data not backed up is data meant to be lost.

Optical Drive

Optical Drive information coming soon

Fans and Cooling

Fans and Cooling information coming soon

Power Supply Units

Power Supply Units information coming soon


Misc. information coming soon

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