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How to Build a Computer, Lesson 2: Choose and Buy Your Parts


Now that you have a better understanding of what goes into a computer, it’s time to actually choose and buy the components you’re going to use. In this lesson, we’ll show you how to most effectively pick out your parts.

Important Considerations for Each Component

Even with the following steps, this process is going to feel overwhelming—especially if you don’t keep up with all the latest hardware news (as many of us don’t). Thus, along with feedback you might find elsewhere on the net, these summaries should help you find the right parts for your particular build.

Note that these descriptions are bound to become outdated as time goes on, so in addition to reading the information below, check out some pre-built systems comparable to what you want to build. That’ll help you figure out what kind of processor applies to mid-range builds, how much RAM you’d find in a high-end build, and so on. The Logical Increments PC Buying Guide is a nice cheat sheet too, that gives you a few recommended builds for different levels of performance (and it’s regularly updated, at least for now). You should also consider the operating system you want to run, and the programs you’ll be using, and check their recommended system requirements. Make sure you avoid bottlenecks, where one component can’t reach its full potential because another part is too slow. We’ll mention a few reputable brands in each category, but we recommend reading up on when brand really matters (and when it doesn’t) so you don’t fall into that trap.

The Processor (CPU)

Picking the “right” processor isn’t as important as it once was, but you should still do a little research so you don’t end up wasting money. There are a few things to look at when shopping for a processor, but let’s start with the basics: clock speed and number of cores. A processor’s clock speed determines how many instructions one core can carry out in one second. Thus, higher clock speed means your computer carries out instructions faster, while more cores means it can carry out more sets of instructions at one time. Some programs can utilize multiple cores at once, making them extremely efficient with multi-core CPUs, but also multitask well since they can carry out multiple sets of instructions simultaneously.

At the time of this writing, low-power machines probably only need dual-core processors, mid-range builds will probably want quad-core processors, and high-powered machines will definitely want quad-core or above (or quad-core processors with hyper-threading). Within those categories, you’ll then want to look at clock speed to determine how fast that processor is.

For something like gaming, clock speed is more important than number of cores, since most games are not designed to use more than one or two cores (though this is starting to change). Assuming you never do any CPU-intensive tasks, a quad-core is probably the highest you need—no hyperthreading or extra cores needed. If you’re converting video, though, the program you use might support multiple cores, in which case a higher number of cores is more important. Check with some of the programs you’ll use most often to see if they support multiple cores and which feature benefits you more.

Those are two basic metrics, but they aren’t the only ones, and you don’t want to rely on them alone. Generally, if you pick a brand and a number of cores, you’ll end up with only a few “families” of processors to choose from, within which you can compare clock speeds since you’re comparing to otherwise identical processors. But if you’re comparing outside of those families, clock speed and cores will only mean so much. I recommend looking at benchmarks for the processors you’re interested in, to get an idea of how they compare.

Be sure to look for other features you may need, too. If you aren’t gaming, you’ll want to make sure your CPU supports integrated graphics (so you don’t need a graphics card), and if you’re going to be using virtual machines, make sure your CPU supports Intel’s VT -x or AMD-V.

Not all processors are created equal, and these are certainly not the only characteristics to compare, but that should help narrow down your choices a bit. Again, if you aren’t hip to all the lingo, ask around! There are lots of people on the aforementioned forums that would be happy to help guide you.

Brands to Watch For: AMD and Intel are the two CPU heavyweights. Intel’s processors tend to perform better, while AMD’s processors are generally less expensive.

The Motherboard

As you look at motherboards, you’ll want to pay attention to quite a few things. Here are some of the more important features:

  • Socket Type: Your socket type (such as AMD’s “AM3” socket, or Intel’s “LGA 1150” socket) determines which processors you can use with that board. So, if you’ve already narrowed down the kind of processor you want, this is a good first step to narrowing down your motherboard. Look for a model with a socket type that matches your processor to ensure that the two are compatible.

  • Size: Motherboards generally come in three sizes: Mini ITX, Micro ATX, and full ATX. The more advanced features you need, the larger the motherboard will need to be, which will also determine the size of your case (and final machine). Generally, your motherboard will be dependent on these other factors, but if you absolutely need a super small machine, you’ll want to filter your choices to reflect that.

  • Number and Types of external Ports: Look at the ports available on the motherboard. Do you need a lot of USB ports? You’ll either want a motherboard that has them or enough PCI slots to support extra USB adapters. Do you need HDMI out? If you aren’t using a graphics card, make sure your motherboard has the right video output for your monitor. How many USB 3.0 ports do you want? Some have more than others. If you’re set on a motherboard that doesn’t have a feature you need, you can add most with expansion cards, but life is always easier if the motherboard has them built in.

  • Amount of supported RAM: If you plan on having a lot of RAM in your machine, you’ll need a motherboard that supports it. Look at how many slots your board has, and how much RAM it allows for.

  • Integrated Graphics: If all you’re going to do is browse the web, use Microsoft Office, and perform other simple tasks, you may be better off choosing a motherboard with integrated graphics. You only need to shell out for a separate graphics card if you’re playing video games, and maybe if you’re playing HD video (though some integrated graphics chips can even do that nowadays). If you’re getting a separate graphics card, it doesn’t really matter if your motherboard supports integrated graphics or not.

  • Number of SATA Ports: This determines how many internal hard drives and optical drives you can have. For most builds, this is only really a concern if you plan on having a lot of drives in your computer (like if you’re building a server or a NAS).

  • Number of PCI Slots: You can only have as many expansion cards as you have PCI slots, so if you want a dedicated video card (or two), extra USB ports, extra LAN ports, a Wi-Fi adapter, or other expansion cards, you need to make sure your motherboard has enough of them.

  • Chipset: Your motherboard’s chipset determines a lot of the more advanced features it has. Some chipsets support overclocking, some do not. Some support SLI and Crossfire (using multiple video cards in tandem), some do not. Others support SSD caching. Others are better for turning into Hackintoshes. If you didn’t understand any of the things I just said, you probably don’t need to pay too close attention to this—but if you want certain advanced features, chipset will narrow your selection considerably.

These are the things you want to look for as far as features go (we’ll consider more things, like price and customer support, in the next lesson when we start shopping). Generally, the more of these features you require on the motherboard, the larger in size and price they become, so keep that in mind as you ponder.

Brands to Watch For: ASUS, GIGABYTE, and MSI are probably the biggest names in motherboards. However, BIOSTAR and ASRock are well known for good budget boards, if you’re trying to keep the cost down.

The Case

Your case may not seem like a super important part of your build, but it’s about more than looks. A good case will be easier to build in, last you a long time, and keep your machine cool. Here’s what you’ll need to look for:

  • Size: Cases come in a number of shapes and sizes, and what size case you choose should match the kind of motherboard you’re buying. If you chose a Mini-ITX motherboard, then a Mini-ITX Tower or Mini-ITX Desktop box is for you. A Micro ATX mini tower is the size you’ll find in most pre-built computers, so know that mid and full towers are probably bigger than what you’re used to. Unless you’re going for a very high performance computer with many drives, expansion cards, and water cooling, a full tower is probably overkill for most users.

  • Airflow: This is something you’ll have to look for in user reviews. Every case is a little different, and the better your fans are placed, the better airflow you’ll have inside (which will keep your computer from overheating).

  • Noise: While you want good airflow, some fans are particularly loud, which can be annoying to some people. If you want your computer to stay relatively quiet, check the user reviews and see what people say about the case’s loudness.

  • Number of Drive Bays: If you need more than just a hard drive an optical drive, count the number of drive bays on your case and make sure you have enough. Keep in mind other things, like card readers, will take up drive bays as well. Internal 3.5” drive bays are for hard drives, external 3.5” drive bays are for card readers, and external 5.25” drives are for optical drives (and other stuff). Note that you can also buy adapters that’ll fit 3.5” card readers in a 5.25” bay, if necessary.

  • Ports on the Front: Almost every case you buy will have a number of ports on the front, which usually include a few USB ports, a headphone jack, and a microphone jack. If you want easy access to USB 3.0, for example, you’ll want to make sure it’s on the front of your case.

  • Cable Management: As you build, you’ll realize there are a lot of cables inside a computer. Unfortunately, if you just leave them hanging where they fall, they’ll block a lot of air from flowing correctly through the case, so you want to organize them as best you can. Some cases have built-in holes through which you can route cables, while some leave you to figure it out yourself with zip ties. The former is, obviously, a lot less work, so see what user reviews say about cable management options.

  • Look: Last but not least, you want to get a case that you think looks good. After all, you’re going to have to look at this thing for the next few years, so it’s worth getting one that isn’t an eyesore in your office. Want one with lots of lights? Go for it. Want one with a side panel window so you can see your handiwork? Show it off! Want a subtle black box that doesn’t call attention to itself? You can get that too.

Keep in mind that a case is something you can use for multiple builds down the road, so it’s okay to spend a bit more money on it. You don’t need to buy a new case every time you build a computer. Get a quality one now and it should last you two or three computers into the future.

Brands to Watch for: Corsair, NZXT, Antec, and Cooler Master both make some of the best cases on the market. Termaltake, Rosewill, BitFenix, Fractal Design, Silverstone, and Lian Li are also well trusted manufacturers.

The Memory (RAM)

RAM seems simple, but you need to make sure it’s compatible with your motherboard. When looking at RAM, think about:

  • Amount of RAM: At the time of this writing, 4-8GB seems to be the average for a normal machine. If you’re running virtual machines or using other RAM-hungry apps, you might want 8-16GB, but most machines should be fine with around 4GB. Keep in mind that RAM is easy to upgrade, and if your motherboard has four slots, you can always get two sticks now and add two more sticks later. There’s no need to get a ton of RAM now in the name of “futureproofing”.

  • Channels: Your motherboard will support either dual, triple, or quad channel RAM. This decides how many sticks of RAM you get. If you have a dual channel motherboard, you’ll want to buy RAM in sets of two—for example, two 2GB sticks for a total of 4GB (or four 1GB sticks). Triple channel motherboards take RAM in sets of three, and quad channel is most optimal with a set of four or eight sticks.

  • Type: Most RAM nowadays is “DDR3”, though DDR4 is starting to pop up. You shouldn’t have to worry about this too much. Just check your motherboard’s spec list to find out what type of RAM it supports and buy accordingly.

  • Speed: Your motherboard will support a number of different RAM speeds (e.g., “800/1066/1333”). When you buy your RAM, it will have one of these numbers attached to it. RAM speed traditionally doesn’t make a huge difference, but it’s starting to become more useful. Buy what you can afford, and make sure your motherboard supports it.

I know that’s a lot of specs to worry about that don’t really have practical meaning, so here’s an example. If I’m buying RAM, the first thing I do is look at my motherboard’s spec list. It says that it’s dual channel, and that it supports 240-pin, DDR3 RAM at speeds of 800, 1066, and 1333. If I want 4GB of RAM, I would use Newegg’s power search function to find DDR3 RAM that came at those speeds. Then I would narrow that down further by looking for packs of two 2GB sticks. It’s much simpler than most other compnents.

Brands to Watch For: You won’t find a huge difference between brands. Popular brands include Crucial, Corsair, Kingston, PNY, OCZ, G.Skill, Mushkin, and Patriot. Again, reading reviews of specific sticks of RAM can be very helpful.

The Graphics Card (GPU)

Choosing a dedicated graphics card is one of the hardest parts of the process. If all you need is something that can play HD video, you don’t need to go too crazy—find a well-reviewed card under $100 and call it a day (or just go with integrated graphics). However, if you’re gaming, you have a lot more to think about.

Instead of looking at the specs, it’s usually easier to just read reviews and look at gaming benchmarks. Passmark ranks cards by straight-up performance tests, and Anandtech benchmarks many cards using real-world gaming situations. Think about your budget for a video card, then try to find the best performing card in that price range. I’ve found that $250-$300 is a good price to performance sweet spot if you want to play games on relatively high settings. If you don’t mind playing on lower graphics settings, you can spend less. If you want something that can play games at very high resolutions (or play those high settings well into the future), spend more.

Some manufacturers also factory overclock their cards, which gives them a performance edge over other manufacturer’s version of the same card, so be on the lookout for those. Also be on the lookout for versions with different levels of VRAM. Higher VRAM cards are useful for high resolution or multiple monitor gaming, but are more expensive.

Lastly, you may have heard about running two video cards in SLI or Crossfire, which has its place, but is something we generally don’t recommend. Unless you’re at the very high end, you’ll be better off buying one card for twice the price than buying two cards.

Brands to Watch For: The two main chipset manufacturers are NVIDIA and AMD. The battle between them both is pretty close, and which one is “better” fluctuates with time, and with each card that comes out. Unless you’re using Linux (for which NVIDIA has better support), I’d worry more about the individual cards than the chipset manufacturer. Go with whatever gives you the best cost to performance ratio at your price point by looking at the above benchmark tool.

When it comes to the card manufacturers themselves, you have a few to choose from. Look for brands with good cooling and good customer support—XFX and EVGA both have pretty fantastic warranties on most of their cards, which is why they’re two of the most popular manufacturers around. MSI tends to have very good cooling. Other popular brands include ASUS, ZOTAC, and Sapphire.

The Hard Drive(s)

When it comes to specs, there are a few things you want to look for in your drives:

  • Size: Obviously, you want enough space on your hard drive to hold all your data, with room for expansion. Hard drives are pretty cheap and easy to upgrade, so you can always add more later if you’re on a budget.

  • Speed: The faster your hard drive is, the faster your computer will boot, launch programs, and open files. These days, you probably want to look for a 7200 RPM drive.

  • Solid State Drives: If you really want a fast drive, you can shell out for a super-fast solid state drive, but you’ll probably still want a regular drive in addition to the solid state one, since they tend to be quite small. That said, if you have a big enough budget, an SSD is one of the best upgrades you can make to a machine, so we highly recommend them. If you choose to go SSD, try to get a motherboard that supports SATA 6Gb/s, which will take full advantage of those speeds.

Brands to Watch For: Western Digital, Hitachi, Samsung, and Toshiba are all good choices. Seagate is also popular, though it has lately gotten a bad reputation for low reliability. Most hard drive manufacturers have a lot of mixed reviews, but I’ve tried all of them and had good experiences.

When it comes to solid state drives, most people recommend Samsung, Crucial, OCZ, Corsair, and Intel.

The Optical Drive

If you’re buying a CD or DVD drive, you probably won’t find a ton of difference between the different models. Most burn discs at around the same speeds. If you’re looking at Blu-Ray drives and Blu-Ray burners, though, pay attention to the read and write speeds. The higher the read speeds, the faster you can rip a Blu-Ray disc, and the faster the write speed on a burner, the faster you can burn a Blu-Ray disc. Obviously, you’ll have to pay more for higher speeds.

Brands to Watch For: It doesn’t make a huge difference who you go with here. Lite-On, Samsung, Sony, and LG are all great manufacturers and the prices should be pretty much the same. The only difference you might find is in the software they come with, but unless there’s an advanced feature in the software you know you want, chances are you’ll never notice a difference between them all.

The Power Supply

The power supply is actually one of the most important choices in your build. This is not an area you want to skimp. Reviews on the net are rarely useful, either, with the exception of a few reputable sites like Jonnyguru.com. The best you can do is buy from a good brand (see below) and look for these features:

  • Wattage: Obviously, if you have a low performance machine, you’ll need fewer watts to power it than you would a high performance machine. Use this power supply calculator to find the necessary wattage for your build, once you’ve picked out the other parts. Generally, give yourself 100 more watts than that calculator says you need, in case you end up upgrading the computer or using that power supply in a later build.

  • Efficiency: Most units will have a percentage value that denotes how efficient they are. For example, an “80 plus certified” 400W PSU will actually pull something like 500W from your wall. So look for something with a high efficiency, as they’ll run cooler (but they probably won’t save you a ton of money).

  • Cable Types: Try to look for a “modular” power supply if you can. This means that the cables come detached from the power supply, so you can use only the ones you need and not have the others wasting space in your case. Also make sure it comes with long cables, since cables that are too short can make your life difficult.

  • Noise: Like your case, your PSU is going to contribute a lot to the amount of noise your system makes. Efficiency will help bring it down, but it’s also worth checking user reviews to see which PSUs tend to be louder than others.

Brands to Watch For: This is one area where you don’t want to be thrifty. It’s hard to keep track of all the brands out there, but quality manufacturers include Corsair, Enermax, Enhance, Fortron/Sparkle/FSP Group, Hiper, PC Power & Cooling, Seasonic, SevenTeam, SilenX, XClio, and Zippy. Note that some of these manufacturers actually build power supplies for other brands, like Antec, Cooler Master, Silverstone, Thermaltake, Rosewill and others—but it’s sometimes hard to tell which ones are the well-built ones. This is one area in which the phrase “you get what you pay for” is very, very true—spend the extra $20 if given the choice; you don’t want to end up skimping and frying a $700 machine in the process.

Note: Many cases actually come with power supplies, so if yours does, you don’t necessarily need to buy one separately. That said, the power supplies you’ll buy separately are usually better than the ones that come with cases, but it’s up to you. It’s just something to watch for when you’re shopping for these two parts.

Extra Cooling

Almost all CPUs come with a heatsink and fan, which are necessary to keep your CPU from overheating. However, many people advocate getting an aftermarket CPU cooler for better performance and lower noise. In addition, if you buy a processor labeled “OEM”, you’ll need a heatsink.

You can find many good heatsinks for quite cheap—just make sure they’re compatible with your CPU socket, fit in your case, and get good reviews. If you really want to get advanced, you can try water cooling, which is even cooler and quieter than air cooling. You can get some good all-in-one water cooling units or build your own (warning: not recommended for beginners or people looking to save money).

Lastly, if your case only comes with one or two fans (or none at all), you may want to buy some extra case fans to keep your computer cool. Just remember: the more fans you have, the louder your computer will be.

How to Select and Shop for Parts

Before you run out and buy everything, it’s important to have a few shopping strategies under your belt so you get the best parts for your machine at the best price you can.

Where to Shop

I rarely get all my parts at one place. Newegg.com is most people’s go-to source for computer parts, since they have an incredible selection and a well put together site. However, don’t neglect your local computer shop—sometimes, you’ll find better deals at places like Micro Center or Fry’s—plus, going to the store can be fun!.

Generally, I shop for my parts on Newegg, then see which of those parts are available at my local shop and at what prices (PCPartPicker is a great tool for this). Then, I’ll buy what I can at the store, and order everything else on Newegg or Amazon. Be sure to put those deal-hunting skills to good use, too. Photo by Bryce Edwards.

Spec Lists and Reviews

Even if I’m not ultimately going to buy from Newegg, I always do my “shopping” there. Its prices are sometimes higher, and its return policy isn’t very good, but the selection, product reviews, and spec lists are better than you’ll find anywhere else. They’ve also got a great advanced search engine that helps you narrow down your choices considerably, which makes the whole process a lot less overwhelming.

One’s shopping process might go like this:

  1. Start with the first part on your list (say, the processor). Chances are you don’t know the difference between all the different models out there, so look at some of the comparable pre-built systems to see which ones are higher-end and which ones are lower-end. You can also check out what people recommend at Reddit’s Build a PC forum, the Logical Increments buying guide, and of course, Lifehacker’s list of the best PC builds.

  2. Head to the corresponding section of Newegg’s store (i.e. “CPUs/Processors”) via the Computer Hardware tab at the top, and, if necessary, narrow down your selection with the categories on the right (say, Desktop Processors).

  3. On the left sidebar, you can filter items by price, manufacturer, socket type, and other characteristics on the left. I also recommend using the “Power Search” button at the top of the sidebar, which can conduct more advanced filtering.

  4. Once you have a short list of parts that fit your needs, you’re ready to go into research mode. As you start clicking through items, you want to look at two things: the “Details” tab, which shows that part’s specs, and the “Feedback” tab, which is chock full of user reviews from hardware geeks who generally know what they’re talking about. Look for good reviews and bad reviews, and look for trends throughout. Just because one or two guys got a part dead on arrival and gave it one star doesn’t mean it’s a bad part—those things happen. But if every other review you read says “this processor runs hot”, or “this case doesn’t have enough room for a PCI card”, you should consider how those flaws might affect your build, and if that part is worth its downsides.

  5. Once you’ve narrowed your choices down to one or two parts in that category, move on to the next category on your list and repeat the process. Once you’ve gone through them all, you can then narrow it down further to one part in each category.

Again, now is a good time to take your list(s) and put them on PCPartsPicker, which lets you easily create parts lists and compare prices. From there, you can start shopping.


This seems like an overwhelming amount of information, but the more research you do and the more opinions you get from experienced computer builders, the easier it’s going to be. Don’t be afraid to take your time picking out parts, and don’t be afraid to ask for help. You’ll thank yourself in the end. And be sure to come back tomorrow night, when we’ll be talking about how to actually put the computer together.


Check out the full Lifehacker Night School series for more beginners lessons covering all sorts of topics.