How to Select Components to Build a Desktop Computer

Introduction: How to Select Components to Build a Desktop Computer

Someone requested an instructable on how to select components to build a desktop computer.  Apparently I am that guy who plays requests now.  All I get are requests to play cover songs, when all I really want to do is to play my own music! ... Oh wait that is something different.

This instructable will involve some research, there is no way around it.  If you are the type of person who does not like to do research stop reading this instructable now, and buy a fully assembled computer.  I am sure that you will be happy with a Small, Medium, or Large computer.  You have to be happy with exactly the components that the company (a.k.a. the man) selected for your computer, and use all the connectors and components that you paid extra for!

Those of us smart artistic types build their own computers!  Sure it will take some research to find computer parts that work together, but the experience will be totally worth the work because you will be so much smarter than those who stopped reading and bought a fully assembled computer.  So bring on the research!

I use several web sites to buy computer components, such as New Egg, Tiger Direct, Mwave, and Amazon.  If you know of other sites please leave a comment so we all can get a good complete list.

Use the different sites to compare prices and to see what different components are available.

This Instructable submitted by the Rabbit-Hole Maker Space as part of the Instructables Sponsorship Program.

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Step 1: Select the Central Processing Unit

The first decision is selecting the Central Processing Unit (CPU).

You have (basically) two choices of CPUs AMD or Intel.  This instructable will not discuss alternate CPUs because buying motherboards for other architectures is much more unique and much harder to find parts.

A CPU contains billions of transistors and a lot of time and effort went into the creation of the central processor.  Therefore the CPU is often the most expensive part of the computer.  It is the brain of the computer where all the computations are done.  Faster or more powerful CPUs are more expensive.

The advantage of picking out your own CPU is you get to decide what features you want to pay for.  Some may want to do some virutalization, others may want to overclock a CPU to get extra speed out of it, while others may want to buy a CPU for lower power consumption.


Advanced Micro Devices (AMD) is a manufacturer of processors for the consumer market.  AMD makes processors that are compatible with the x86 architecture.


The Intel corporation is another manufacturer of processors for the consumer market.  Intel is the inventor of the x86 architecture. 

Both companies make a wide range of different processors that compete very closely with each other.  Each year the processors get smaller, faster and have more features.  The companies focus on different processor features to differentiate themselves from the competition including cores, cache, and speed. 

Socket type

The CPU will connect to the motherboard in what is called a CPU socket.  A motherboard will only have one type of socket so selecting the CPU will help limit the choices of motherboards.

Select a processor with the features that are important for the anticipated use of the computer.  Once you have a CPU selected note the socket type.  The type will be needed when looking at motherboards that will work with the CPU.

Step 2: Select the Motherboard

The motherboard is a printed circuit board (PCB) that nearly everything on the computer plugs into. 

CPU Socket type

The CPU you selected in the previous step will narrow down the selection of motherboards because you have to find a board with a compatible CPU socket.  For example the Intel CPUs code named Haswell use the socket 1150 (there are 1150 connections on the CPU) and you need to buy a motherboard with the 1150 socket type.  There are often many motherboards to chose from with each socket type. 

The manufacturers further differentiate themselves by the types of devices that can connect, the amount of devices, and the size of the board itself.

Types of devices

Always check the motherboard description for types of devices that will connect.  These kinds of devices could be USB 2.0, USB 3.0, Firewire, Thunderbolt, ESATA, etc.  Some motherboards come with extra features such as WIFI or built-in sound cards.  These extra devices will differentiate the prices.  Try to select a motherboard with only the devices that you will use.  Look at pictures of the back of a motherboard where all the devices plug in.  Ask yourself a couple of questions:  Do you have a device with that kind of plug?  Will you use that feature that costs extra? 

Amount of devices

The motherboard manufacturers can add extra SATA ports or more USB devices to their products that will differentiate them from the other manufacturers.  Try to anticipate the purpose of the computer and how many devices will need to be attached.  For example if the computer will store a lot of data having extra SATA connections would be nice.

Size of the motherboard

The size of the motherboard will determine what kind of case you will buy.  The standard size of a motherboard is Advanced Technology eXtended or ATX.  This standard size creates a base where other manufacturers can build from.  If you require a smaller computer select a Mini-ATX or microATX form factor.  Beware that the smaller formats have limitations on types of devices (a large video card may not fit in a microATX case for example).

Select the motherboard that is right for your application.  The socket type is the biggest factor here.  If the CPU socket type does not allow you enough options on motherboards go back and re-evaluate your CPU selection.

Step 3: Select the Memory

Random Access Memory (RAM) is the memory your computer uses while it is running.  The computer needs enough memory to run the operating system and all the running programs.  When the computer runs out of RAM it stores some memory to the hard drive (paging) and that process is much slower.  Adding more RAM to the same computer causes less paging and can make the computer appear to run "faster".


The motherboard selected in previous steps will determine what type of memory to buy.  This instructable will not describe every type of RAM out there (there are too many types).  Just check the specifications on the motherboard to determine what type of RAM will fit in the socket.  Get the pin count and narrow the search to that type of RAM.


You need enough RAM for the operating system and the running programs.  It is difficult to determine how much memory a computer will need before you build it.  Some operating systems publish minimum RAM requirements, but remember that is a minimum just for the operating system.  If you want to run any programs then you will need more memory.  If you want to play games on the PC you will benefit from even more RAM.  


Some memory is faster than others.  Most RAM is very fast and the difference in speeds would be very hard to detect.  Computers only can access the RAM at one speed.  If there are multiple RAM capable of different speeds the lowest common speed is what will be used.  If you are adding to existing RAM make sure to get equivalent or better speed. 

Select the size and amount of RAM that the computer will require.

Step 4: Select the Computer Case and Power Supply

The case that will hold the computer parts.  Some cases can handle multiple formats but make sure the motherboard size (ATX, Mini-ATX, microATX) is supported before selecting the case.

The case's main job is to hold the components and keep them from overheating.  Most cases will come with fans and have options to add more.  You will want to make sure that your case has a fan to move air in and out of the computer to avoid overheating your parts.


There are different form factors in computer cases.  The standard desktop form factor will lay flat on the desk under the monitor.  Another common form factor is a tower that normally sits on the floor next to the desk.  There is a full tower, that has the most space, the most common mid tower, and a mini tower with the least amount of capacity.  The Mini-ATX and microATX motherboards allow for some very small computer cases, but that may limit the amount of internal devices that will fit in the computer (video cards or hard drives).

The larger computer cases can often accept more than one size of motherboard.  A mid tower case may handle ATX or Mini-ATX motherboards.  Select a computer case that can accept the form factor (size) of the motherboard.

Power Supply

The Power Supply Unit (PSU) is a very important component of the computer.  Without reliable, consistent power the computer will not run correctly.  The main factors for selecting a PSU is to buy one that has enough Watts to handle all the devices in your computer.  You can add up the Watt requirements of the CPU, motherboard, hard drives, video cards and any other devices in the computer to get a general number.

Some computer cases come with a power supply.  These included PSUs are often inexpensive to keep the over all cost of the computer case lower.  Beware of inexpensive power supplies, if the PSU fails or is unreliable the computer will not work.  More expensive PSUs will have more Watts, more efficiency (bronze, silver, gold, platinum levels), a better warranty and more reliability.

Select a power supply that works for the components in your computer.

Step 5: Select Storage

There are many different kinds of storage but this instructable will only describe hard drive storage.  The operating system, documents and files are generally stored on hard drives this is the type of memory that is retained after the computer is powered off.

Hard Disk Drive

A Hard Disk Drive (HDD) is a storage device that uses rotating disks with magnetic material to store data persistently.
Solid State Drive

Solid State Drive (SSD) uses integrated circuits to store data.  These types of drives are muchfaster and more expensive than typical HDDs.  Select an SSD only if speed is essential and the additional cost is acceptable.

A computer needs a least one means of storage and there are not many variables in this decision just interface and size.


Hard drives have different interfaces or ways that they will connect with the motherboard.  There are Paralell ATA (PATA, also known as IDE, or EIDE), Serial ATA (SATA), Small Computer System Interface (SCSI), or Serial Attached SCSI (SAS).  Most consumer grade computers use the SATA interface.  Which ever storage you select be sure the interface is supported by the motherboard.


The same rules apply here:  more memory costs more money.  If there is room you can often buy additional hard drives and connect them to the same motherboard. 

Select the size and type of storage based on the anticipated use of the computer.

Step 6: Select the Video Card

Some CPUs and motherboards come with graphics built in, and this will be sufficient for every day uses.  If the computer will be playing games you will need to add on a video card.


There are different interfaces for video cards, Accelerated Graphics Port (AGP), Peripheral Component Interconnect (PCI), and Peripheral Component Interconnect express (PCIe).  The first two interfaces are obsolete, most modern consumer grade computers use PCIe only.  Check to see what interface the motherboard supports and only buy a video card with the same interface.


There are two main companies that make graphics chipsets Nvidia and ATI.  Several other companies take the chipsets from Nvidia  or ATI and create a video card Printed Circuit Board (PCB).  The two companies are very competitive and try to distinguish their chipset from the other with different features.  Some manufacturers put more memory on the video cards while others increase the clock speed.  Perform an internet search for companies which review and compare video cards with benchmarks and display the data in graphs.

Select a video card that works best for your requirements (usually the game you want to play) and fits in the motherboard and computer case

There if you have selected the parts you are ready to build a computer from parts.  Have fun!

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    9 Discussions


    4 years ago

    There is one website that you can add that is VERY helpful for those who are building a computer:
    There you can select each part of the computer and it will let you know if there are any compatibility issues and it gives you the prices, who is selling them, if there are any sales, specials, coupon codes, etc. and if there are any combination deals with other parts. It will let you know what the shipping costs and if there is any Free shipping. And you can save your Build ideas for future reference!!


    6 years ago

    Try Pc Case Gear, there Australian but it wouldn't surprise me if they have stores located over seas, they have alright prices but have a very large variety of components. A long with all the specs of each part.


    6 years ago on Introduction

    I don't know if you can answer this here, but I've heard of something called a "hackintosh". Is it possible/legal to use this guide to build a machine that can load some version of OS X?


    6 years ago on Introduction

    Wow, this is a very awesome 'ible! This is exactly how I would write it. When I saw the first diagram, I knew that you were doing it right. You used the correct hierarchy for selecting components. I am very impressed.

    I just had a few things. Explain the limitation x86 processors have on the amount of RAM you can have (4Gb max). That is very important, especially as applications become more demanding in the future. You want to be able to upgrade.

    Under storage, just mention that SSDs come in much smaller capacities, and will be very expensive to get capacities of 500Gb +. Also, make sure they know PATA is very obsolete, haha.

    Explain that PCIe has different sizes (x16, x8, etc) and that they need to watch out for that when buying graphics cards, sound cards, NICs, etc. Usually graphics cards are x16, but it varies. It is very important that they check out what the motherboard has, and what the PCIe card requires. Also, x16 cards often require an extra power cable from the PSU, so they need to make sure that the PSU they select has that extra cable.

    Also on the topic of graphics cards. Mention that if you have more memory on the card it self, it will use the RAM less.

    One thing I like to do, I add a step at the very end of my tech 'ibles that has a quick list of definitions for "geek jargon" which I throw out. Things like thunderbolt, SATA, etc. One point of confusion I see a lot of people getting caught on is the use of the word "memory". Some might think you are talking about storage capacities rather than RAM, haha. You could have a * and explain at the end of the step, or whatever you want to do.

    Other than that, there are a few grammatical mistakes, sentence flow, but over all a very awesome Instructable! It was weird reading this, it sounds a lot like how I write my 'ibles.


    Reply 6 years ago on Introduction

    Most of the modern 32 bit operating systems (Microsoft XP and newer) can handle more than 4 GB of RAM with a technique called Physical Address Extension (PAE).  Therefore I did not put anything in about RAM limitations.


    6 years ago on Introduction

    I bet this would meet the requirements of the I Could Make That competition. Rather than buying a computer "off the shelf", you can build your own! I would consider adding your other 'ible as well.