How to: Build your own PC

Just recently i have built a new PC for a family member who wanted to upgrade from a four year old PC that was starting to struggle with the latest apps. Every time i build a new PC it’s different, technology moves so fast that no two builds the same. A number of things can change depending on the price point of the build. In the enthusiasts arena at the top end of the spectrum hardware is evolving at a blistering pace, new chipsets are being developed, processors are getting faster and drawing less power, GPU’s are getting faster and drawing more power, and memory and disk space is getting progressively cheaper. In the budget arena at the bottom end of the spectrum components are being integrated to cut costs, product designs are getting simpler and cheaper to manufacture, and the overall accessibility of the Personal Computer is now much greater and widespread than it ever has been before.

I’m definitely an advocate of DIY PC building. It’s not that complicated, PC components are like a giant Lego set, they generally only fit in one hole. The hardest part is finding the right components and making sure everything is compatible. But with a little help from the internet and some good advice you can quite easily build your own PC in very little time.

Why should i build it myself?

The main benefits of building your own PC instead of buying one off the shelf are:

1. Cost Savings

Building a PC yourself can save you significant money. Labour costs from smaller PC specialists can be pretty expensive for such a simple task and package deals in the larger stores are very rarely good value, they might seem cheap but ultimately you get what you pay for. One of the great things about building a PC yourself is that you get to shop around for the individual components, finding the best deals on-line and buying components separately.

2. Quality

You could significantly improve the quality and overall specification of the build for the same price or less than the larger store’s pre-made package PC. Yes the big stores have buying power but they also have high running costs and still need to make a decent margin.  Cut out the middle man and buy the components directly, you can then make the decision on which components you need to spend more on, which components you can live without, and which components you can save some money on by opting for the budget ‘no frills’ model.

3. Performance

CPU, Memory, Graphics, Storage all come in various makes and models. Some are better than others. All of these components will have a direct impact on the overall performance of your PC. If you use Microsoft Windows you have probably already seen the “Windows Experience Index”. It basically gives your key system components a score based on a scale of 1 to 7.9. I’m not a big fan or advocate of this in particular but it serves as a basic reference point for identifying the key components present within any PC and the correlation that has on  some kind of “Performance” metric. There are far better methods to benchmark performance but we won’t get into that now.

Which components do i need to spend money on? 

As mentioned above the key components that make a real difference to a PC’s overall performance are the CPU (Central Processing Unit), the system Random Access Memory (or RAM), the GPU (Graphics Processing Unit) and the system Storage (or Hard Disk Drive – HDD, Solid State Drive -SDD), in that order*.



CPU (Central Processing Unit)

This is the heart of your PC, where all the system processing is done, this is one of the key components that really counts towards noticeable performance gains in everyday computing tasks. The mainstream manufacturers are AMD and Intel. Both have their own unique chipsets which will influence the selection of the motherboard. The typical number of cores found on a CPU is increasing as technology develops, gone are the days where a single core CPU is standard, we have moved on from dual core processors, now quad core is the norm, at least for now (Research hyper-threading and virtual cores for more in-depth information). Most modern CPU’s now also include integrated graphics, which makes a dedicated graphics card unnecessary for most basic needs. The current Intel range starts with the I3 model, then the mainstream workstation I5 model, and finally the performance / enthusiast I7 model. The current AMD range starts with the Phenom multi-core (quad) desktop model, then the A-series (A4, A6, A8, A10 model) CPU with integrated Graphics (APU), and finally the performance /enthusiast 8 core FX model. The key performance value for all of these processors, regardless of the manufacturer or model, is the core clock speed (also referred to as the operating frequency), represented in GHz. There are many other important factors like the the RAM frequency, if it’s unlocked for over-clocking potential, does it have hyper-threading, how many virtual cores, total power consumption, all of which are best left for another article, in the interests of keeping this as simple as possible. You should be looking for a 64-bit processor and operating system.



RAM (Random Access Memory)

Another significant contributing factor to the PC’s overall performance, the system memory or RAM. The information held in the system RAM is accessed directly, instead of being read sequentially as is the case with all other types of storage, this makes it quicker to access and read, and is primarily used for caching information required by the CPU. This type of memory is volatile, meaning if power is lost the data it holds is also lost, a key distinction between other types of storage, for instance the Hard Drive. The more of this memory your system has the less it will need to write to the hard disk during processor intensive tasks, making the overall computation task much more efficient, and faster to complete. There are a few things to consider when buying system memory, the first is making sure the type of memory is compatible with you motherboard. Most motherboards support DDR2/DDR3 (Double Data Rate) memory, where information exchange happens twice for every DRAM clock cycle. If your motherboard supports it, many memory modules come in matched pairs, so that they can be installed in a dual channel configuration, often represented by colour coding the memory slots on the motherboard. CAS Latency, or CL refers to the response time (specifically the delay in response) between the memory controller requesting information from a particular memory module address, to the data being made available. The lower the latency, the better the performance. How much memory do you need? To be honest probably less than you think, but given that the price of memory has dropped so much over the years and the noticeable difference in performance gained from having more of it available, i would recommend you get at least 4GB (1x4GB module in single channel configuration), for any new system, but ideally 8GB (2x4GB in dual channel configuration) if your budget will stretch to it. There is rarely any need for 16GB*.

* Based on a family orientated PC for general web browsing, office work, playing music and video, some light gaming. If it’s a special purpose PC for video editing, CAD, high end gaming then this might not always be the case.



GPU (Graphics Processing Unit)

You may need to sit down with a stiff drink when you see the price of some modern dedicated graphics cards, but don’t worry, you don’t necessarily need to blow your entire budget on the latest cutting edge graphics card. Think about what you want from your new PC, how you are going to use it day to day. If you’re using it for general office work, word processing, internet browsing, video playback you may not even need a dedicated graphics card, the on-board integrated graphics will do the job just fine and you can save yourself a couple of hundred pounds. If however your needs extend beyond all but the most basic everyday tasks, you should definitely consider a dedicated graphics card. The on-board graphics are great but at the same time they are a little lacklustre. If you want to do any kind of gaming you need a dedicated graphics card, the same is true for professional image designers (heavy Photoshop use) or video editing use. There are two mainstream manufacturers, AMD (who acquired ATi in 2006) and Nvidea. AMD’s product line is called Radeon (HD), while Nvidea’s product line is called GeForce (GTX). As with the CPU, the key things to look for in any GPU are clock speed (higher is better), and the amount of dedicated video memory (more is better), but also key to a GPU’s performance is the number of video processing streams (again more are better). To complicate matters, Nvidea have a proprietary system called CUDA, and they generally list the number of CUDA cores present on any GPU. By contrast AMD list the number of stream processors on their products. By and large CUDA cores and stream processors are effectively the same thing, they both represent the GPU’s number of floating point maths processors, although it’s not a good idea to compare them side by side, they don’t necessarily perform in the same way. In a similar fashion Nvidea encourages game developers to use CUDA, their proprietary system, while AMD use OpenCL, which is as the name suggests is an open standard. Nvidea cards can use both CUDA and OpenCL, where as AMD cards can only use the latter. Basically there are pro’s and cons’ to both standards, you don’t really need to think about this when buying a new GPU, but it’s good to be aware of it. Most dedicated graphics cards now use the PCI-Express (x16) interface, so you should look for this on both the graphics card and the motherboard. PCI-Express superseded the much older AGP (Accelerated Graphics Port) as the standard graphics interface. One last thing to note, some motherboards support two dedicated graphics cards, for twice the graphics processing power. For AMD cards you need a motherboard that supports CrossFireX in order to run two cards in parallel. For Nvidea cards you need a motherboard that supports SLi Crossfire in order to run two cards in parallel. In both cases, if you intend on running two dedicated graphics cards you must have a PSU that supports it, and that can cope with the additional power required. Personally i would recommend a single more powerful GPU over two less powerful GPU’s, as this will yield the best results, is far simpler and also cheaper.




For the best performance you should definitely consider a Solid State Disk (SSD) for your boot drive/primary hard disk. They cost more, generally have less storage space but they are much much faster (almost instant read with no seek time) due to no moving parts, also they consume less power, are more durable and much quieter. It’s advisable to install the Operating System and all your core software on the SSD, both of which will benefit from the increased read speeds, making your PC boot the OS and load applications much quicker. A traditional often larger Hard Disk drive is recommended to accompany the SSD for any other file storage needs. Alternatively you might consider a hybrid drive which combines both the Solid State Memory and a traditional hard disk platter. These are a good option if you want a single hard disk with a larger storage capacity.  I recommend at least a 128Gb SSD for your boot/OS drive. This should give you adequate storage for both the OS and your core applications. If you can afford to stretch to a 256GB or 300GB drive then it’s probably worth the investment in the long term.

SATA (Serial ATA) is the type of bus interface commonly used to connect mass storage devices to the motherboard, the same interface is also used for optical drives, like a DVD or Blu-ray drive. You need to have enough SATA ports on the motherboard to accommodate all these devices, and you can only have one device per port. Most motherboards have at least six internal SATA ports, and also now usually have a external SATA (or eSATA) port for an external drive. The latest commonly used revision is SATA 3.o (often described as SATA III). This revision is capable of 6 Gbps transfer speeds, double that or the previous revision SATA 2.0 (SATA II) which was only capable of 3 Gbps. You should always go for the latest revision to benefit from the faster transfer speeds, however if you already own SATA I or II devices modern motherboard storage controllers are backwards compatible, you just won’t benefit from the faster transfer speeds.

Quality is pretty consistent across all the major manufacturers like Samsung, Intel, Corsair, Crucial, Kingston and OCZ for SSD’s and then Western Digital (WD), Seagate and Toshiba for traditional hard drives. When looking at SSD’s the performance benchmark is shown in either IOPS (inputs/outputs per second) or read/write speeds, measured in MB/s, obviously the quicker/higher the  value the better.  With traditional hard disks there are a couple of other important factors, like the seek time which is shown in milliseconds (ms) where the lower the value the better the performance, the on-board cache size (typically 32mb or 64mb, 64 being preferred), and finally the revolutions per minute (RPM) which indicates how fast the platter spins, which is typically 5900 RPM for storage and non performance enhanced drives, 7200 RPM for everyday desktops, and 10,000 RPM for performance / enthusiast use. As you might expect, the faster the spindle spins the more noise the drive makes.

Western Digital have a unique classification for their products using blue, green, red and black which i think summarises the traditional hard disk offerings quite well. Their everyday budget desktop drives or secondary hard disk drives are blue, their eco-friendly low power consumption drives are green, their performance desktop high end drives are black, and their enterprise storage class drives are red.

For an average family use computer i would recommend a 256GB SSD for the primary drive where the OS and the applications are installed, and a secondary traditional 1 or 2 TB (blue or green) drive for file storage.



Power Supply Unit (PSU)

It’s definitely not a good idea to skimp on the PSU. A cheap PSU is like a ticking time-bomb, waiting to pop (they literally do pop) potentially taking with it all of the other expensive components. That said, there is a lot of scaremongering on-line which may make you think you need a 850w PSU when in fact all you really need is a reliable and well built 500w PSU. Out of all the advice in this article, this is really the only part I’m hesitant about writing. Because it’s always the component i deliberate on the most when i myself am building a PC. I usually start with a moderate sized PSU, then get worried that i have underspecified the wattage, go way overboard, then go back to what i had in the first instance. Basic rule of thumb, buy well known respected brands, like Corsair, Seasonic, XFX, Enermax. Look for high efficiency ratings (bronze, silver, gold), most power supplies have a maximum 85% efficiency, so make sure to recalculate the PSU’s maximum wattage based on the stated efficiency. If you plan on running multiple graphics cards buy a PSU that’s SLI or CrossFireX certified and has more available watts (look for 650-700w minimum). In most modern PC’s the graphics cards are the power guzzlers (avg 130 – 200w per card), then the CPU (anywhere between 65w and 150w for modern CPU’s), then the Motherboard (differs depending on what’s integrated, 150w max for on-board graphics chip, audio, network), then the Hard Disks and Optical Drives (each averaging between 30w – 60w per unit),  finally the memory (typically 30w max per memory module). Fans consume almost no power at all (5-6w max per fan). Leave out the fancy neon lights and side window case, i have been there and it’s really not cool, the novelty soon wears off. You probably don’t need a modular PSU, yes it’s a nice idea and it makes installation easier, also it helps cable management as you simply don’t install cables you don’t need, but this is a nice to have, it’s definitely not a necessity.

So add up the wattage of each component to give you your total maximum power requirement, add some headroom, say 20%, and this gives you a rough estimate of your total power requirement. Run this calculation past one of the PSU calculators listed below, check your calculation somewhat resembles the calculation shown on the site (they are never anywhere near accurate, they vary wildly, just use your common sense when comparing the two) and then if your still unsure post your shopping list and your power calculation on one of the self build forums listed below and ask for a second opinion.

* Based on a family orientated PC for general web browsing, office work, playing music and video, some light gaming. If it’s a special purpose PC for video editing, CAD, high end gaming then this might not always be the case.

Which components can i save money on?



Main-board (Motherboard)

The system Main-board or Motherboard is a key component for any system, however you really don’t need to buy a motherboard that has every feature under the sun if you’re simply never going to use them. Most people don’t need overdrive or over-clocking aids, unless you’re an enthusiast who wants to squeeze every last bit of performance out of their hardware by pushing it to the extreme limits beyond which potentially lies a broken motherboard, burnt out power supply and a cooked CPU.   The key features most people will need are things like enough I/O (Input/Output) ports, for USB, Firewire, HDMI, Video and Audio. Some people may want some internal expansion ports for SATA, if they intend on adding a new Hard Disk or Optical Drive at some point in the future. For this reason when selecting a motherboard make sure it has the things you need and nothing more. One thing you must consider however is that the motherboard is compatible with the other system components, it has to have the same chipset as the CPU, must support the memory frequency for the RAM, and have the correct interface for the Hard disks and GPU. The motherboard is effectively the common link or interface between all the other components, as the name would suggest.



System Chassis (Case)

The system case, again these range from the budget to enthusiast, but this is where i think you definitely can save some money. Because lets face it, most of us don’t really care what the system case or chassis really looks like, most of us want something that is quiet, functional, and inconspicuous looking. It will probably spend it’s life hidden away as much as possible under a desk, so why spend hundreds of pounds on it. I personally believe that even some of the cheapest cases are more than adequate for the job, many people will disagree with me, and i understand their viewpoint, as i have spent that kind of money on a case myself in the past. I recently purchased a case for  £28.31 (inc VAT), it was the cheapest branded make i could find at the time. I wasn’t expecting much, but when it arrived i was pleasantly surprised at the quality of the construction and the design. It even came with 2 120mm case fans pre-installed, i was expecting to have to buy these separately. It featured a tool-free installation, something which is usually only for the more expensive enthusiast cases. Their was plenty of room inside the case for all of the components, including the full length graphics card. By comparison this case compares very well to a much more expensive case i purchased previously, the key differences are in the structure of the chassis, a more expensive case will have different internal compartments to maximise airflow and cooling, removable drive caddies to make installation easier, and better sound proofing to minimise noise. I highly recommend you don’t buy a case which includes a PSU, as they generally don’t fit good quality PSU’s as it ramps up the cost significantly. Buy a PSU separately following the advice given above. You do need a case with good air flow, you should look for a case with a front (intake) fan and a rear (exhaust) fan. Larger fans are better as they move air more efficiently at lower RPM, which also means less noise. Do not underestimate the amount of heat generated by a modern PC, if you get a chassis with inadequate air flow expect your system to overheat causing instability and potentially serious damage.



CPU Cooler / Heat-sink fan (HSF) 

Now lets be clear, cooling is absolutely mandatory, you can’t do without and you don’t want to skimp on a cooler, it has to serve it’s purpose which is keeping the CPU cool under heavy load by dissipating the heat generated quickly and efficiently. For general use, the stock cooler which comes with the CPU is sufficient*. If it wasn’t sufficient then they wouldn’t be able to bundle it with the CPU. A couple of points to note here are that modern CPU’s can and do run quite hot under heavy load with stock cooling. I have seen Intel Core i5 4670 temps reach 70°C, even mid seventies under stress testing with the stock cooler at stock voltage and clock speed. That is quite hot, but not abnormal. Had i been building that PC for gaming, or processor intensive use, where the CPU would often be put under that kind of load for extended periods of time i would of replaced the HSF for a better one in a heartbeat. As it’s normal use is general office, image editing, i know the temps will rarely rise above 40°C, which is well within the comfort zone for any modern CPU. Use some common sense, buy a CPU cooler that is appropriate for the intended use of the system. If your a gamer, looking to over-clock the CPU, then you should definitely replace the stock HSF, and if pushing it to the extremes, consider other cooling solutions like liquid cooling.

* Based on a family orientated PC for general web browsing, office work, playing music and video, some light gaming. If it’s a special purpose PC for video editing, CAD, high end gaming then this might not always be the case.

Other optional components

Optical Drive (BD-ROM/DVD-ROM) – I always include one, if nothing else it makes the OS install easier, although there are other ways. Software distribution is changing, more software is now distributed on-line.

Multi-card Reader – Useful thing to have and doesn’t cost much. Essential if your into photography or image editing. 

Floppy Disk – I haven’t used a floppy disk now for years, hardware drivers are usually distributed on CD or available for download from the vendors website. Floppy disks are dead, good riddance.  

How do i know which components are compatible? 

Do some research. There are many websites available which offer system building or PC customisation tools which can check all the selected components are compatible and appropriate for each other. These websites are also useful for making sure you haven’t forgotten anything important, like the motherboard or CPU cooler. Another good idea is to find a pre-built or package PC from one of the larger PC retailer websites, look at the detailed specification and then try to match it using the system building or PC customisation website. This will allow you to swap out components to suit your personal needs, find cheaper alternatives,  ensure they all fit together and are compatible. Finally it will serve as a check list so that you can be sure you haven’t missed anything, some even run a compatibility report which will notify you if you need a bigger PSU, or a different motherboard.

But remember, when it comes to buying the components, shop around. You don’t need to buy everything from one store, in fact to maximise your cost savings i generally advise you don’t. Look for components which are on special offer, or bundles which include the motherboard, CPU+Cooler and RAM, they often represent good value with reasonable cost savings.

Where can i go for good advice if I’m unsure or need help?

Ask a geek. We all know someone who gets their kicks from building PC’s, fixing PC’s, upgrading PC’s, “works in IT”, or has an air conditioned server room at home (complete with raised floor) in the basement where the laundry should be. They probably won’t mind helping, in fact they will probably be happy to help given that you want to build your own PC instead of buying one from PC World or Wal-mart. If they do mind you can always try one of the more popular PC hardware forums, there are many which specialise in DIY PC builds, although be warned not all the advice you get is guaranteed to be good advice, go for the majority vote, not the person who shouts the loudest.

Useful Links / Further Reading

Self Build / Compatibility Websites – PC Build configuration website, with compatibility checker and PSU calculator. – Check out the on-line system configuration page. – Check out the configure a desktop page. – Check out the 3XS custom shop.

Recommended On-line PC Component Retailers – Scan stocks all types of PC components, PC bundles, they also offer custom builds. – Stocks all types of PC components, PC package deals, peripherals and consumables. – Stocks all types of PC components, peripherals and consumables.

DIY Build Forums / Online Help – Check out the ‘review my build’ thread, post your shopping list here and ask for a comments/feedback.

PSU Calculators (As a point of reference only)

eXtreme PSU Calculator – Specify what internal components you have, and it will calculate the minimum and recommended PSU wattage (more accurate, perhaps under compensates)
Corsair PSU Finder
– Specify what processor and video card you have, and it will recommend a suitable Corsair PSU (over compensates)


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