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How To Build A PC: From Component Selection To Installation

How To Build A PC: From Component Selection To Installation
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A great many of the folks who land on Tom's Hardware are already deeply passionate about technology and PC hardware. But we know that others are looking to learn more. We're an inclusive bunch. So if you've never built your own PC, fear not. Our editorial team does it all of the time, and we're happy to walk you through the steps, starting with picking the right parts.

There's a good chance that, even if you haven't gotten your hands dirty inside of a case, you still have a basic knowledge of the components that go inside. Experienced builders often have their ideal configuration in mind before they choose a case. But even a seasoned pro needs to be sure that everything's going to fit inside the right chassis. And of course, enclosures vary depending on what you want to do with your PC. Home theater systems, all-in-ones, flashy gaming boxes, and business-oriented workstations all have their own requirements.

Traditional cases follow the size categories below. However, more modern designs tend to stray from those well-defined standards in the name of differentiation. Mid-tower designs, for example, are now found in nearly full-tower scale. To make matters more confusing, they can even be referred to as full towers, even if they lack the drive bays inside that used to define the form factor.

Traditional Case Sizes
TypeFull TowerMid TowerMini TowerMini CubeDesktop
Height21-24 inches17-19 inches12-14 inches7-9 inches3-7 inches
Width6-8 inches6-8 inches6-8 inches8-9 inches14-17 inches
5.25" bays4-93-61-21-21-3
3.5" internal bays6-122-61-21-22-4
Motherboard Form FactorATX, EATXATXmicroATXmini-ITXATX, microATX
Card slotsSevenSevenFourTwo2-7
Power supplyPS/2 or largerPS/2PS/2 or SFXSFX or TFXVarious

Full towers were traditionally tall enough to hold two power supplies, though many had a second hard drive rack where you might expect to find the top power supply. The interior space of a full-tower chassis is useful in some configurations; however, most mainstream users (and even most enthusiasts) simply don't have enough hardware to fill it.

A better justification for picking a full tower is that the top bays are easier to reach when the case is sitting on your floor. A modern example of the traditional full tower, Rosewill’s Blackhawk Ultra, is the right-most case in the image below.

ATX mid-towers are usually capable of holding full-sized motherboards, full-sized power supplies, several full-sized optical drives (DVD and Blu-ray burners), and multiple hard drives. Well-designed units like the Cooler Master Storm Enforcer (above-left) are well-suited for gaming and video enthusiasts, simply because they support a greater number of expansion cards and hard drives than smaller units. A comparison of our current case reviews to models from ten years ago show that good ideas stand the test of time.

A majority of cases give you room for seven expansion slots around back. Typically, that's enough for a couple of graphics cards, add-in sound, and even back-panel brackets exposing USB or eSATA connectivity. But let's say you love your games, and you're dead-set on building a system with three or even four graphics cards. Specifically seeking out an ATX case with eight or more expansion slots might be necessary, since high-performance cards have thick cooling solutions that use the case’s slot hole for support and ventilation.

MicroATX mini-towers are nearly as versatile as mid-towers in applications ranging from office workhorses to high-end liquid-cooled SLI-powered gaming monsters because of their less-imposing profile and easier trasportability. Mini-towers typically support one or two optical drives and one or two hard drives, and the microATX form factor supports a maximum of four expansion slots. All of those limitations are acceptable for most users.

Mini-ITX cubes typically support a single expansion cards and only the smallest power supplies, though the slightly-oversized Lian Li PC-Q08 above (center) supports larger parts. Relying mostly on integrated features and capabilities, these space-saving enclosures were once only good as office- and productivity-oriented platforms. Now, thanks to more efficient host and graphics processors, we also have access to ultra-compact gaming machines and home theater consoles. Though you'll commonly see these referred to as “small form factor”, the term form factor is better applied to the mini-ITX motherboard found inside. Variations of the cube aesthetic alternatively support ATX and microATX form factors.

Formerly used to raise small CRT monitors up to eye level on flat desks, today’s horizontal desktop cases are mostly restyled for home theater systems. They range from the gaming-themed mini-ITX Raven RVZ01 (pictured bottom-center, above) to the eight-inch-tall full-ATX pedestals laying on their sides. Many of the slimmer models use special half-height expansion cards, though the model pictured above uses a right-angle adapter (called a riser card) to situate a full-sized graphics card sideways. If expansion is important to you, beware of models that use a custom-sized power supply, as those may not be upgradeable.

Want something smaller? The yellow box above is the most compact unit we’ve tested to truly qualify as a performance-oriented machine. Called the Brix Pro, it holds two notebook-sized memory modules, an on-board mSATA SSD, and a 2.5” notebook drive. Shorter single-drive units are available with similarly scaled-down performance, and Intel even jumped on the tiny bandwagon with its similar-appearing NUC (Next Unit [of] Computing) form factor. Most of these machines are available either as a barebones system (no drives or memory) or a complete PC, and all of them use external, notebook-style power adapters.

Display 33 Comments.
  • 6 Hide
    gofasterstripes , June 23, 2014 2:11 AM
    Can I once-again say a big "Thanks" to the Tom's team for writing a great article which will save me lots of time and hassle in explaining PC building and component selection to n00bs who ask me for help.

    Cheers!
  • -1 Hide
    JOSHSKORN , June 23, 2014 2:57 AM
    What about NUCs and cases alike? Yes, I realize those are too small for discrete GPU cards, but depending on your usage and space, it just might be what one needs.
  • 4 Hide
    Crashman , June 23, 2014 3:06 AM
    Quote:
    What about NUCs and cases alike? Yes, I realize those are too small for discrete GPU cards, but depending on your usage and space, it just might be what one needs.
    It's addressed in the last two sentences of page 1:
    Quote:
    Intel even jumped on the tiny bandwagon with its similar-appearing NUC (Next Unit [of] Computing) form factor. Most of these machines are available either as a barebones system (no drives or memory) or a complete PC, and all of them use external, notebook-style power adapters.
    There's really nothing more to say. You don't build these from separate components, you just finish them with a drive and memory as you would any of the other systems covered in this article.
    Quote:
    Can I once-again say a big "Thanks" to the Tom's team for writing a great article which will save me lots of time and hassle in explaining PC building and component selection to n00bs who ask me for help.

    Cheers!
    You're welcome!
  • -1 Hide
    revanchrist , June 23, 2014 3:25 AM
    Should put in a Cooler Master Elite 110 to showcase a mini-ITX instead of that huge Lian-Li.
  • 1 Hide
    illuminatuz , June 23, 2014 3:47 AM
    Guess most of the issues in the forums will be ironed out by this one simple post..
    Wonderful as usual toms.. Appreciate it..
    :D 
  • 1 Hide
    rolli59 , June 23, 2014 5:46 AM
    Most if not all issues brought up on the forums have answers in some or the other article on Tomshardware. This article compiles answers to build questions.
  • 1 Hide
    AMD Radeon , June 23, 2014 6:37 AM
    This article is very good reference newbies asking how to build PC in toms forum.
  • 0 Hide
    DookieDraws , June 23, 2014 6:54 AM
    Long time reader of Tom's Hardware, even before I finally became a member. This has been a very helpful site to me and my friends over the years. In fact, this IS our go-to site for when we need to figure something out. I am always learning something new.

    Great article! No doubt this is going to help a lot of folks.

    Thanks, guys!
  • 1 Hide
    Yuka , June 23, 2014 7:25 AM
    Very good write up guys.

    I think you missed a section for "SLI - XFire", but it's great overall. Since its a guide for folks with little to no knowledge, I think it would help them to dispel myths and get some facts over XFire and SLI.

    Cheers!
  • 2 Hide
    Xeres Forteen , June 23, 2014 7:53 AM
    Good article with excellent info. I'm going to just add my 2 cents on how I like to do the actual assembly of the PC after receiving the parts.

    First I put the motherboard into the PC (not fastened) to see where the standoffs are going to be placed onto the case. Also I note what routes I'm going use for my cabling. Then I take the motherboard out and insert the standoffs and port plate into the case. Also I take my case cables (power sw, reset sw, USB, front audio and mic cables and put a twist tie around them all and place them near where they are to be plugged into the motherboard. These cables are easy to lose track of.

    Next I place the power supply, and "bay devices" (optical drives, non-removable storage, etc) into the case and have those cables attached and either hanging over the outside of the case or routed behind the motherboard tray. This obviously depends on how you determined the cables will be routed earlier.

    Then I take my motherboard, put the CPU, RAM, and cooling system on as much as I can. Then I place the whole thing into the case - usually at an angle at first, leading with the side with the RAM (which is normally going behind the case bays in smaller cases) in first.

    At this point it's just a matter of aligning the motherboard with the standoffs and port plate. Plug it all in (including the case plugs which are conveniently out of the way and together).

    Power it all on and volia!
  • 1 Hide
    Onus , June 23, 2014 8:03 AM
    I would like to have seen the article begin well before case selection, with questions as to purpose for the build. Define the purpose, then you know what sort of parts you'll need for it. The case is often the last component I choose, and only once was the first, when the purpose was to build the smallest system possible that would meet my needs.
    Otherwise, it was a good article. People who are uncertain of building their own PCs can learn a lot from it.
  • 0 Hide
    zelgar , June 23, 2014 9:10 AM
    I'm a little confused with the section dealing with Choosing your Power Supply. If the power requirements of the components is 647 W as shown in the example, how could you use any power supply that isn't designed to higher wattage? Is it expected that only 85% of the design load will ever be used (i.e., that you wouln't be using the max energy requirements of all of your components at the same time)? Wouldn't it be better to have your power supply based upon the max usage of the components since this may occur (e.g., running a modern game at max settings that your computer can run)? Aren't Power supplies rated Bronze/Silver/Gold/Platnium at 80% of the Power Supplies capacity, so you'd want a PS that is would be running at 80%+ at max load (e.g., 647/.80 = 809 W or 647/.85 = 761W)?
  • 1 Hide
    Damn_Rookie , June 23, 2014 11:35 AM
    Quote:
    I'm a little confused with the section dealing with Choosing your Power Supply. If the power requirements of the components is 647 W as shown in the example, how could you use any power supply that isn't designed to higher wattage? Is it expected that only 85% of the design load will ever be used (i.e., that you wouln't be using the max energy requirements of all of your components at the same time)? Wouldn't it be better to have your power supply based upon the max usage of the components since this may occur (e.g., running a modern game at max settings that your computer can run)? Aren't Power supplies rated Bronze/Silver/Gold/Platnium at 80% of the Power Supplies capacity, so you'd want a PS that is would be running at 80%+ at max load (e.g., 647/.80 = 809 W or 647/.85 = 761W)?

    The 647W is measured at the wall socket, as the article mentions input power. After taking into account the 85% efficiency of their power supply in this example, the PSU is only outputting 549.95W to the PC components at max load. Adding some headroom they come to the 600W PSU recommendation.

    Personally I'd like a little more headroom, but the calculations in the article are correct.
  • -1 Hide
    zelgar , June 23, 2014 12:00 PM
    I think the article will confuse noobs of talking about the power measurement at the wall socket versus the power rating of the power supply. If the sum of the power requirements of the computer components is X, they need a power supply the provides more than X. Making them aware that the power supply will be using more energy than X at the wall is useful to know so that people don't buy a PSU that is too wasteful. Since undersizing a PSU is more catestropic than oversizing one (e.g., crashes/boot faiolures vs electricity costs) getting one that meets the needs of the components is the starting point of evaluating PSU.
  • -1 Hide
    n3cw4rr10r , June 23, 2014 12:37 PM
    I usually buy my pc components from Amazon. #1 customer service. They dont give you any bs. Hell they even send you a pre-paid shipping label to ship the item back. I have never had they charge me a "re-stocking" fee on any item, even when I returned item because I did not like it.
  • 0 Hide
    PapaCrazy , June 23, 2014 1:16 PM
    After all this time, why do I still get the most excited about the cases? Maybe cuz the components are logical forgone conclusions, but the case is the artistic, subjective bit? I don't know, years at this stuff and a sexy case still turns my head. The mobos are starting to look really sexy nowadays too.
  • -1 Hide
    Jim Maher , June 23, 2014 3:03 PM
    Great article! This is a wonderful overview, and should prompt most readers to research their more detailed questions on the forums.

    Building your own is great fun, and most serious users should probably give it a try at least once in their lives. Given that, I'd recommend an annual "refresh" of this article, with updated info and re-validated links to corresponding reference articles and resource forums.

    A great service to your readers!
  • -1 Hide
    chaz_music , June 23, 2014 5:24 PM
    Excellent article with lots of interesting information.

    I wanted to comment on the power supply part of the article. One is the efficiency and the total cost to use versus the front end purchase cost. A less efficient system will obviously create more total heat as wasted energy. But aside from possibly making someones room rather uncomfortable, it also increases your airconditioning energy use. A good rule of thumb is that an AC system will use 50% of the heat energy. To add the total annual cost, multiply that times the percentage of the year that the AC is on. So your example of a 647W system with 85% PSU would give (550W used):

    647W - 550W = 93W at plug

    93W * 50% = 47W AC energy

    Total Energy (summertime) = 93W + 47W = 140W

    If the AC were on the while year and the PC were on continuously, this is about $140 annually, or almost $12 per month added electricity in the summer. If you did the same thing with a cheap 70% efficient system, you get $248 annual cost which is $20.63 per month summertime cost. At a difference of $8, it does not take many months (of continuous on!) to make the more efficient PSU make much more sense.

    The other topic I wanted to comment on is ESD. I am an engineer and work with ESD issues everyday. It is a very real an poorly understood issue by many because of the often hidden or delayed failures that it causes. ESD many time causes walking wounded damage without an immediate failure, which finally fails several months later. And if you look at websites sell PC parts, many people complain of DOAs. Many, many DOAs are caused by ESD. Memory, CPUs, motherboards, HDDs, and other sensitive systems are often returned as DOA, driving up the cost of the PC enthusiast market and adding frustration. In research texts, they estimate the global electronic failures due to ESD to be 40-60% of the total failures over product life.

    So that little $5 ESD wrist strap is money well spent. Buy one and reduce your heartburn.

    Charles
  • 1 Hide
    Crashman , June 23, 2014 5:49 PM
    Quote:
    The other topic I wanted to comment on is ESD. I am an engineer and work with ESD issues everyday. It is a very real an poorly understood issue by many because of the often hidden or delayed failures that it causes. ESD many time causes walking wounded damage without an immediate failure, which finally fails several months later. And if you look at websites sell PC parts, many people complain of DOAs. Many, many DOAs are caused by ESD. Memory, CPUs, motherboards, HDDs, and other sensitive systems are often returned as DOA, driving up the cost of the PC enthusiast market and adding frustration. In research texts, they estimate the global electronic failures due to ESD to be 40-60% of the total failures over product life.

    So that little $5 ESD wrist strap is money well spent. Buy one and reduce your heartburn.

    Charles
    The vast majority of "DOA" returns are for undamaged products (simple things like having a standoff or cable in the wrong place that caused power fault/no boot/no damage are number 1, followed by fraudulent returns at Number 2). And the majority of damaged products have physical damage from the amateur technician cramming things together. I used to be in that business.

    The only problem with wrist straps is that most people don't want to be "tied" to anything. They're a great idea that's really rarely needed. Feel free to say otherwise if you live in the desert.

  • -1 Hide
    cutiemech , June 24, 2014 12:31 AM
    Skimmed through it but didn't saw anything about tools required for assembly like what screwdriver etc
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