Build a PC From Scratch

The first thing we need to do is select our parts. Picking parts can seem overwhelming, but even modern PCs only need basic components. These are, in no particular order: a main processor (the central processing unit, “CPU”), a CPU cooler, system memory (the volatile, temporary data storage known as random access memory, “RAM”), storage (like a solid state drive, “SSD,” or hard disk drive, “HDD”), a motherboard to connect everything together, and a power supply.

For tower PCs, some CPUs have built-in or “integrated” graphics processors, but if not (or if you want to play games or run other graphics-heavy programs), you’ll need a dedicated, discrete graphics card (graphics processing unit, or “GPU”). To top it all off, it’s smart to stuff all of this into a case (with fans) for streamlined cooling and dust control.

Now that we have the list, let’s take a look at each one and shed light on what you’re looking for as you plan and pick parts.

Let’s start with the main processor. At the time of writing, there are two mainstream CPU platforms: Intel and AMD. They trade blows, both offering competitive performance and features. There’s no clear go-to and rarely a time where one company is hands-down the best option. So what do you pick? The right choice wholly depends on your use-case, priorities, and budget. Ask yourself: do you want to game at high fidelity with less concern with refresh rate? Or, do you want to prioritize competitive, fast paced games with more weight given to refresh rate over resolution? Do you plan on streaming? Video editing? Your specific list of needs is unique—as a general tip, keep that in mind when accepting advice or copying part lists from online guides.

Your needs will also inform the distribution of your budget—and which parts you want to spend more on. If you crave high resolutions, more budget might go to a GPU, for example. If your goal is a video rendering workstation, more budget might go to a more expensive CPU with a higher core count. Midrange offerings are usually adequate for gaming—think Intel Core i5 or AMD Ryzen 5. Try to keep your hardware choices balanced, too. There’s caveats to every rule, but if your budget allows for a high-end GPU, it’s normally best to avoid lower-end CPUs. Contrarily, if you’re constrained to an entry-level GPU, you don’t need a Core i7, Core i9, Ryzen 7, or Ryzen 9 chip. Consult review sites like Tom’s Hardware or PCMag for thorough deep-dives into specific CPUs and recommended CPU-GPU pairings that are accurate for the year, month, and week that you’re building.

Pro tip: Avoid the biased comparison site UserBenchmark.

Size matters — there are multiple “form factors” that PCs fit into, ranging from miniature Intel NUCs to gigantic workstations. Based around motherboard sizing, the most common standards are Mini ITX, Micro ATX, and Standard ATX — think of these as small, medium, and large. ATX is the most common, but consider the space your PC will live in as well as your general preference. The size you choose will determine the size and type of motherboard. There are also different size power supplies for different form factors. Don’t stress too much here — there are many different case types that accommodate most size combinations. In general, small cases need small motherboards and small power supplies.

Your CPU choice will directly dictate your motherboard choice. Each CPU uses a specific socket, and sockets can change each generation. It can be tough to keep track of what motherboard sockets and chipsets work for any given CPU, so don’t hesitate to take full advantage of online compatibility checkers, our favorite being PCPartPicker. If you input your CPU, the site will automatically give you available and supported motherboard options. You can then sort by price, memory and storage support, port selection and quantity, etc.

Additionally, as you add more selections, the page will also present you with various warnings for size constraints, software requirements, and other things to consider. You can filter by size, too, to narrow down the options that’ll work for you.

Computer processors need help to keep their cool. Some CPUs, if purchased new, come with a “stock” cooler. While these are usually adequate for the CPUs they ship with, more often than not you’ll want to purchase a third-party CPU cooler. Consider your CPU and its heat output: how much cooling do you really need—and do you have enough? Generally, lower-end CPUs with less cores generate less heat than higher-end processors with fast clocks and high core counts. Size and fitment are also a factor: will your choice interfere with your case? Check dimensions of your other chosen components. PCPartPicker-like websites can also be extremely helpful here. Don’t forget to consider your personal preference, though. There are black, white, and RGB coolers with numerous shapes and designs. There are even water coolers (more on that below). Beware! A lot of new PC builders overspend on coolers. If you’ve found a cooler you like, shop around for similar features—you might find a better deal.

While we aren’t covering complex, custom water-cooling loops, there’s an all-in-one alternative! Aptly named AIO liquid coolers, these coolers consist of a block with a water pump that mounts atop the CPU and tubes running to a radiator. AIOs can offer (subjectively) superior looks and the possibility of higher cooling potential, but come at the cost of, well, increased cost, and are inherently less reliable than their air-only counterparts. They’re rarely necessary. Don’t choose one for your build without understanding the pros and cons.

When selecting memory, the first thing to check is (yeah, you guessed it) compatibility. Check what RAM type your motherboard supports—DDR3, DDR4, and DDR5 aren’t cross-compatible. Your CPU choice dictates your motherboard choice, and your motherboard will only support one type of RAM. Next, consider capacity. “How much RAM do I need?” is a very common question, and the answer evolves/increases as time goes on. For strictly gaming—and again, at the time of writing—16 GB is enough for a lot of users, but 32 GB can give you nice headroom for more demanding titles, extra Chrome tabs, streaming, etc. If you’re video editing or 3D modeling, you might want to spring for 64 GB or higher. Do your research, ask around, and make a budget-conscious decision. Most of the time, your motherboard will have four RAM slots—and, most of the time, you’re only populating two. You can add more later.

RAM is further categorized by speeds and latencies. There’s more here than we can cover—but ordinarily, the higher the speed and the lower the latency, the higher the cost, and the higher the performance. Be sure to check for specific recommendations for your chosen CPU.

For storage, options abound, and you can always add more down the road. Modern computers benefit greatly from the speeds of solid state drives (SSDs), although spinning hard disk drives (HDDs) are still valuable for bulk storage. I highly recommend the fast, less failure-prone SSD option for the boot drive. This is the drive your operating system (OS) boots off of, and it’s the speed of this drive that partially dictates the overall snappiness of your PC, like the time it takes to power up and open programs. The speeds of extra drives in your system—for games or other file storage—matter less, as they’ll only affect file transfer speeds and load times, not the navigation of your OS.

These storage drives can interface with your computer in a variety of ways, but the most common connections are M.2 and SATA. M.2 drives, namely ones that utilize the NVMe interface spec, support higher read and write speeds and can be installed on your motherboard with very little hassle and no cables—just one socket and one screw. These drives can be more costly, but are extremely beneficial for fast boot times and an overall snappy experience. SATA-based SSDs are cheaper, slower, and decent for bulk storage. Hard disk drives also use the SATA interface, and are usually the best way to achieve large amounts of storage on the cheap. For example, if you’re primarily gaming, you could choose a 500 GB M.2 NVMe SSD boot drive and a 2 TB HDD for game storage. There’s no one right answer here; ask around and get advice if you’re stuck!

The form factor you’ve committed to will set your case options. Most cases offer wide component support. For example, you can technically install a Mini ITX motherboard into an ATX-sized case, although it might look a tad lonely in that large open space. A contentious point of PC building—and the center of heated debates—is case airflow. Some cases may look svelte and sleek, but might stifle airflow as a tradeoff. Feel free to browse case reviews — GamersNexus does a lot of these — to gauge what’ll best fit your specific needs. Cases vary greatly: in how many drives they support, the length of GPUs they support, etc. They vary in shape, color, and quality-of-life features, like types and qualities of included fans, fan hubs, built-in RGB, front panel I/O, etc.—the list goes on and on. Cases are another common area of overspending for new and old builders alike. There are a lot of case manufacturers—don’t settle!

There are three main things to consider in choosing a power supply (PSU): size, wattage, and efficiency rating. PSUs that comply with the ATX standard all have the same length and width, but can vary in depth (i.e. how far it goes into the case). Check case specifications for their max supported power supply lengths. Smaller formats are SFX, SFX-L, and the less common Flex-ATX. If you’re building an ATX or Micro ATX system, chances are any ATX PSU will work just fine. SFX and SFX-L are more common for compact Mini ITX cases.

How much wattage do you need? This is usually dictated by the max power draw of all of your components—you want enough headroom—but there are some general guidelines based solely on your CPU and GPU selections, which are the two most power-hungry components. Lower end systems generally require 450-650W, mid-range systems may need 650-850W, and higher end systems usually fare best with 850-1000W, or even higher. This is by no means a strict rule, and the ranges will change as time goes on. When you have the list (or general idea) of components you’d like to use, ask around and get advice from more seasoned PC veterans for what wattage will work best. The efficiency rating, or “80 PLUS” rating, is a standard which measures how efficiently a PSU can deliver wall power to the PC. It is not a measure of PSU quality. It can be a contributor, but an 80 PLUS Gold rated PSU is not automatically a higher quality unit than, say, an 80 PLUS Bronze rated one. The community has put together various PSU tier lists, most helpful for determining models to stay away from. All told, don’t cheap out on your computer’s power supply. If a PSU doesn’t have a full suite of proper protections (such as current and temperature protections), it can pose a risk to the rest of the components in your system.

Remember, PCs don’t have to be boring! In addition to the base set of components, you can add lights or other frills to elevate your PC from a pile of colorless parts to an extravagant art piece worthy of display. Chances are, you’ve put a lot of thought and time into this, or you’re about to. Take pride in it! Some common “upgrades” are RGB fans, RGB-equipped RAM, and PSU cable extensions. Color coordinate (or don’t), and make it your own. Of course, there are dozens of other components and peripherals you can add to a PC build as you see fit. You may need additional storage, such as an external hard drive or a NAS (network attached storage). You could also add a sound card, network card, optical drive, or additional cooling.

Depending on your needs, you may also want to add peripherals: websites like Tom’s Hardware and PCMag keep up-to-date on the best monitors, keyboards, mice, and gaming controllers for any budget. Watch reviews and get creative! Remember — it’s your setup.

Now that we have some parts, it’s time to build. The best place to start is to prep the motherboard. Because multiple components connect directly to it, it’s easier to install them before the motherboard is wedged into the case.

If you have an anti-static wrist strap, now’s a good time to put that on to properly ground yourself against accidental electrostatic discharge (ESD) damage during assembly. I won’t call it strictly necessary, as modern electronics are pretty resilient, but I highly recommend it for peace of mind. It only takes one instance of an extra buildup of static electricity to shock and kill your new and expensive stuff.

Pro tip: place your motherboard atop its box while you work.

Let’s start with the CPU. The procedure differs based on the socket type and make (Intel or AMD):

AMD socket AM4: This socket uses the “pin grid array” (PGA) design, with the connection pins located on the CPU itself. Lift the socket locking arm out around the locking clip and up to its vertical position (Image 5). Match the corner of the CPU with a gold triangle to the corner of the motherboard socket that also has a small triangle. Grip the CPU by its edges and lower it into the socket, ensuring that all pins fall into their matching holes (Image 6). The CPU should fall into the socket without any pressure. Don’t push the CPU into the socket. When installed correctly, the CPU will sit flush with the edges of the socket, and there shouldn’t be any gaps. Now, close the locking arm by pulling it down, around the locking tab.

Handling an AM4 processor can be nerve-wracking, especially with the delicate pins on its underside. If you accidentally bent some pins, fear not! In most cases, these pins can be bent back.

Intel LGA 1151, 1200, and 1700, AMD socket AM5: These sockets use a “land grid array” (LGA) design, meaning the fragile pins are located on the motherboard instead of the CPU itself. The install is similar for both modern Intel and AMD AM5 sockets. New motherboards may come with a protective plastic insert in the socket — don’t remove this by hand! It pops out automatically when you install your new CPU. Follow any directions printed on this plastic insert. Lift the socket locking arm out around the locking clip and pull it up and back, which will also lift the top section of the socket along with it. For LGA 1700 and AM5, the top section of the socket won’t swing up with it, so lift it up by hand (Image 1 below). For Intel, align the cutouts in the processor with the cutouts in the socket (Image 3). For AMD, match the corner of the CPU with a gold triangle to the corner of the motherboard socket that also has a small triangle. Both CPUs can only go in one way. Hold the CPU by its edges and lower it into the socket (Image 2). Hinge the top section of the socket back down, onto the CPU, and re-latch the socket locking arm under its clip (Image 4).

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There are plenty of great online resources, installation guides, and walkthrough videos for all types of CPUs. If you’re unsure at any step, don’t hesitate to find help.

Depending on the type of CPU cooler you’ve chosen, it may be useful to install it at this stage (Image 10). For all-in-one liquid coolers, it’s easiest to install the pump block onto the CPU later in the process, once the motherboard is secured within the case. For tower coolers, it’s usually helpful to take advantage of the extra access you have now while the motherboard is still outside of the case (Image 7).

CPU coolers should come with sufficient install instructions, and procedures vary greatly between cooler types and brands. Follow the instructions slowly and carefully, and remember—always tighten screws in an X-pattern (i.e. top-left to bottom-right, then top-right to bottom-left), use the correct size screwdriver (or bit) for the job so you don’t strip any fasteners, and don’t forget to remove any protective films from the contact surface (Image 8). Note: If you’re installing a CPU tower cooler with a section of the fin stack or fan that overhangs the RAM, you’ll want to install the RAM first.

Before installing your CPU cooler, apply thermal paste. You don’t need to apply any extra thermal paste if your cooler already comes with it pre-applied. There are many different ways of applying thermal paste that people swear by, and there’s no one right answer. There are, however, some key things to note: Your CPU cooler will spread the paste out naturally when it’s tightened down. You don’t need to manually spread it unless your cooler instructions recommend it. Too much thermal paste might result in a mess, but won’t usually impact performance. However, you want to ensure you have enough thermal paste. The top surfaces of CPUs and the bottom contact surfaces of coolers are anything but perfectly flat (as GamersNexus shows on various occasions) so you want an adequate thermal paste application to fill any microscopic gaps—and again, the cooler will spread the paste thin under pressure. There are many ways to apply thermal paste—we recommend a small squeeze (somewhere in size between a large grain of rice and a small pea) right in the middle of the CPU (Image 9). That’s it!

Now your CPU and its cooler are in. Great job. Next stop, RAM. Your motherboard will have either two or four DIMM (Dual In Line Memory) slots (or more if you have a higher end workstation motherboard). It’s important to always run RAM in dual channel, and this relies on the installation locations of your memory modules. Consult your motherboard’s manual for their preferred installation pattern. Sometimes it’s even printed on the motherboard itself. Usually, if you were to number the slots as 1 through 4 from left to right, the #2 and #4 memory slots should be populated if you’re installing only two sticks. Of course, if you have four, populate all four.

To install a stick of RAM, you’ll first need to unlock the slot. Some motherboards have locking tabs at either end of each memory slot, and some only have one. Unlock the tabs for the slots you’re installing RAM into (Image 11). Now, note the little notch near the middle of the stick. This notch will align with a nub within the RAM slot—forcing each stick to only go in one way (Image 12). Similarly, only DDR4 RAM can be installed in a DDR4 board, and vice versa with DDR3, DDR5, etc. Generations of RAM aren’t backwards compatible. Now that you’ve unlocked the slot and noted the correct orientation of the module, slide the module into the slot and press firmly to latch it into place (Image 13). This may take a surprising amount of force, but you should feel a satisfying click on each end when the module seats completely. Looking from a shallow angle, you shouldn’t be able to see any gold contacts on the stick when it’s properly installed. Repeat for the rest of your memory.

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If you held off on installing the fan onto the tower cooler, now’s the time (Image 14). Our cooler uses metal brackets that secure the fan to the fin stack, but your mounting method may vary—consult your cooler’s manual for mounting instructions. Plug the fan (or daisy-chained fans) into the CPU_Fan header on your motherboard (Image 15). If your fan supports RGB, now’s the easiest time to plug that in, too, zip-tying or otherwise securing excess cable slack (Images 16 and 17).

Time for a boot drive. Modern motherboards come with convenient M.2 slots, which remove the need for any cable mess. Some of these M.2 slots may have a heat sink or a decorative fascia that you’ll need to remove before installation (Image 18)—this will be outlined in your motherboard manual—don’t be afraid to read it! There’s also, normally, a preferred slot (or slots) for your boot drive. Some motherboards disable M.2 slots when certain PCIe slots are populated (like installing a GPU). Again, consult your manual.

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M.2 SSDs are keyed, and can only be installed in one orientation. They slide into their slots parallel to the motherboard and are secured with a single (usually Phillips) screw onto a standoff. If there’s a screw pre-installed here, remove it before installing the SSD. Align the SSD with the slot, making sure it’s oriented correctly before applying any pressure (Image 19). When installed correctly, the half-circle cutout at the other end should line up perfectly with the mounting screw hole on the standoff. You can install the screw now—and then the heat sink or any covers, remembering to remove any protective plastic covering thermal pads. Note that sometimes the mounting screw can be integrated into a motherboard shield, if there is one (Image 20). If you’re installing a second M.2 SSD (and your motherboard supports it), you can do that now too, following the same procedure as your boot drive. If you’ve chosen a 2.5” SATA drive for your boot drive (and you don’t have any M.2 drives to install) you don’t need to worry about installing it yet. We’ll do that later!

New cases often need some prep before you can screw down your motherboard. Your case may have come with an accessory bag or box, holding screws, the manual, zip ties, etc (Image 23). Remove that, consult the case manual, and locate the screws for securing the motherboard. Look at where the motherboard will sit. Your case will have pre-installed standoffs that the motherboard will sit on (Image 24). Based on the form factor of your motherboard and case (ATX, Micro ATX, or Mini ITX), make sure you have the correct stand-offs. Miss one, and your board may not be fully secure, have an extra and it may scratch your board, or worse, create a short circuit. Some case manufacturers stamp this information into the case’s sheet metal itself, and others will outline it in the manual.

While you’re working, stash the front and back panels somewhere safe (Image 22), especially if one or both are tempered glass. Some cases secure the panels with knurled thumb screws (Image 21). You won’t need to reinstall either until the PC’s completely done, and broken glass isn’t on the agenda.

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The last step before installing the motherboard into the case is the I/O shield. Some newer motherboards come with an integrated one, meaning you don’t have to install one, but most motherboards have a separate I/O shield. To install it, match the orientation of the port cutouts on the I/O shield to how the motherboard will sit inside the case, and make sure the flat (or labeled) side is facing out (Image 25). Firmly press the I/O shield into the rectangular cutout in the rear of the case, making sure it snaps in securely around its entire perimeter and sits flush (Image 26). Most I/O shields have small metal nubs that snap into place (Image 27). Go cautiously, as the metal edges of the shield can be sharp.

Alright, finally, motherboard time! If your case has a rear exhaust fan, removing it may make motherboard installation easier. Lay your case down on your work surface, back panel side down. Hold the motherboard assembly by the tower cooler, or if you’re waiting to install an AIO, hold the motherboard by its sides or lightly by its built-in heat sinks (Image 28). Slowly lower your motherboard into the case—your goal is to simultaneously slot the ports through their cutouts on the I/O shield and align the board with the standoffs (Image 29). Make sure not to scrape the bottom of the motherboard against any of the standoffs—you don’t want to scratch it. Note that one of the case standoffs near the middle of the motherboard may double as a locating pin—it’ll slot through the middle hole rather than house an opening for a screw (Image 31). When correctly installed, all of the standoffs should align perfectly behind each of the holes on the motherboard and the ports should fit snug and centered in the I/O shield (Image 30).

Install the motherboard screws (Image 32). These should thread in easily—if you feel resistance, double check that you’re using the correct screws and that the motherboard’s still lined up with the standoff underneath.

Pro tip: use a screwdriver with a magnetic tip to access hard-to-reach areas.

Next is motherboard wiring and cable management. Set your tower upright. PCs have lots of cables, so this step may seem long, but fear not! I’ll outline each cable type and where it should go. Your computer also needs power, but we’ll install the power supply and power supply cables near the end. Note that the locations of some of the following cable headers may vary, especially if you’re building a mini ITX system. Consult your motherboard’s manual for explicit locations.

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• Audio: Located at the bottom left corner, this connector enables the headphone and/or microphone jack on the front/top of your case, and it only goes one way. Usually labeled HD_Audio, F_Audio, or similar (Image 33).
• Front panel: Located at the bottom right corner, this cable bundle wires up the power button, power button LED, hard drive activity LED, and reset button, if so equipped. Depending on the case, this will either be composed of individual cables or bundled into one connector. Consult your motherboard and case manuals for which pins are which. Some pins on the motherboard may be unused. Usually labeled F_Panel or similar (Image 37).

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• USB 2.0: Located along the bottom edge, there may be more than one depending on your motherboard. This connector only goes one way. Usually labeled USB_2_1, USB_2_2, etc., or similar (Image 36).
• USB 3.0: Located on the motherboard’s bottom or right edge, this is a larger connector, and the pins on the motherboard are fragile—make sure the cable is seated correctly before pushing it into place. One side has a locking tab that matches the port, and can only be installed one way. Usually labeled USB_3 or similar (Image 38).
• USB Type-C: Located on the motherboard’s right edge, this connector is a newer feature that may not be present on all boards. Additionally, its usefulness relies on the case also supporting front panel USB Type-C—this port may stay unused if your case doesn’t support it, and that’s fine! Usually labeled USB_3.2, USB_3_C, or similar (Image 39).
• System fans: Your motherboard will have a variety of fan headers, namely variations of the following: CPU_Fan, AIO_Pump, Sys_Fan, or similar. Your CPU cooler’s fan should already be plugged into the CPU_Fan header. Alternatively, if you’re using an AIO, you’d connect its “fan” cable (in this case it’s running the internal water pump) to the AIO_Pump header, so the system knows to run this more consistently than it’d run a case fan. If you have more fans than your motherboard has headers, you’ll need to connect the fans together. Some fans support daisy chaining, but if not, you may need a fan splitter—but try to avoid connecting more than 3-4 fans to one header. SYS_Fan headers are for these case fans, and they’re usually scattered around the board. Ideally, connect each fan to its closest header. If your case has a built-in fan hub, it usually connects to one of the SYS_Fan headers (Image 34).
• RGB: Motherboards have two flavors of RGB headers: ARGB 5V (addressable, 3-pin, labeled ADD_Header or similar) and RGB 12V (non-addressable, 4-pin, labeled RGB_Header or similar). Your motherboard may have one or both types, and they’re not interchangeable. Don’t plug an ARGB cable onto a 12V header, and vice-versa! Consult the manual for whatever RGB device you’re connecting for proper procedures. If your case has a built-in RGB controller, you can plug RGB accessories directly into the case instead of the motherboard socket (Image 35).

If you’ve purchased a case new, the case manufacturer may have bundled all of the cables together into a pre-routed position. You may need to undo parts of this bundle and route each cable to the general location it attaches to the board. Cases will have various chassis cutouts for cable routing. Try to use these effectively to reduce cable strain as well as improve the overall organization and look of the finished system (Image 40). Avoid running cables along the bottom of the case, for example. Once a cable is connected and you’re happy with its placement, use the included cable management channels, velcro straps, or zip-ties to secure the cable down on the back side (Image 41). A pair of flush cutters are handy for snipping zip-ties.

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If you’re installing extra fans in your system, now’s the time to do so. Fans secure to the case with unique fan screws, and should be included with your fans (four each). Tightening down fan screws may take a surprising amount of force at first, as the fan screws are meant to cut threads into the plastic holes on some fans. It’ll be easier the second time.

Time to install the power supply and its various cables (Image 42). The installation procedure is the same for all sizes of PSU, whether it’s the “normal” ATX size or the smaller SFX or SFX-L sizes. Select SFX and SFX-L PSUs may include a bracket allowing them to mount to larger ATX spaces. Power supplies, independent from size, come in three modular flavors: fully modular, semi-modular, and non-modular. Modular PSUs have all removable cables, semi-modular have some removable cables, and non-modular have no removable cables.

For modular and semi-modular PSUs, you’ll need to install the cables required for your system into the power supply itself first (Image 44). Most modern cable types are as follows:

• Motherboard 24-pin: The big, wide cable. Required for all builds, this cable sends power to your motherboard.
• CPU 8-pin: Usually in a 4+4 format, not to be confused with the similar-looking 6+2 8-pin cable(s) for your GPU. Also required for all builds, this cable powers your CPU. Some motherboards may come with additional CPU power plugs if your processor requires extra juice, like for intense overclocking. Consult your manual—but for most mid-range builds, the single 8-pin is sufficient.
• GPU 8-pin(s): Graphics card power cables can come in a 6+2 configuration to support GPUs that use 6-pin headers. In this case, the extra two pins will just hang off to the side, unused. Some graphics cards need more power, and come with more headers. Some power-hungry cards can even come with three 8-pin plugs! While some PSUs may come with a cable that splits one 8-pin PSU output to two GPU 8-pin cables, it’s best to use individual cables wherever you can, like two 8-pin to 8-pin cables instead of a one-into-two splitter. The amount of GPU power outputs vary based on your power supply—consult your graphics card manual or online communities for the best setup.
• SATA Power: Used to power SATA devices, like 2.5 inch drives or 5.25 inch drive bays, like CD burners. These can be left out if your system doesn’t use any SATA-powered devices. Keep in mind that sometimes special case components run on SATA power, like fan hubs, RGB hubs, or AIOs.
• Molex Power: Used to power legacy devices that use 4-pin Molex connectors. Non-adjustable speed fans can use this. These can be left out if your system doesn’t need it.

Regardless of modularity, your power supply should come with all cables necessary to complete your build. If something seems to be missing, consult your manuals or find help.

Some graphics cards use newer, alternative power plug styles, like 12-pin and 16-pin Nvidia connectors. If your power supply doesn’t natively support these standards, don’t worry! Graphics card manufacturers usually include adapters.

With the appropriate cables connected to your PSU (Image 45), we’re ready to start routing them. First, slide your PSU into its approximate mounting location, careful not to pinch any of the cables that connect to the motherboard (Image 46). Some cases allow access through the back panel, and some cases require sliding the cables and PSU through the rear cutout. In most cases, the PSU should install fan-down: you should see ventilation through the bottom of the case for it to breathe through. In cases where the PSU mounts up top, the fan might breathe through cutouts in the top panel, or more commonly fan-down, directly into the case. If you’re unsure, consult your case manual—your power supply needs cool, fresh air. You don’t need to secure it down with screws quite yet—it can be easier to let it shift around slightly while you’re routing cables. If your case has hard drive bays inside the case “basement,” note that they might get in the way of your cables. Some cases offer front-to-back adjustment of these cages, so move them closer to the front if you need more room or remove them if they aren’t in use (Image 47).

Route the larger 24-pin motherboard power cable first (Image 48). Find the largest cutout in the case next to where the 24-pin plug is on the motherboard’s right edge, and feed the cable through (Image 51). Pull it far enough through so you can turn the cable around to face the motherboard, and align the pins with the plug. All PSU cables only go in one way—with a locking tab on one side—so make sure it’s oriented correctly before applying any pressure. Once aligned, press down firmly until you hear (or see) the locking tab click into place. The cable should sit flush with the socket. Pull any extra cable length back through the back panel, creating a nice, tight bend when looking from the motherboard side (Image 52). Don’t pull the excess back too tight, though—make sure the socket and motherboard aren’t stressed. On the back side, use cable channels, velcro, and zip-ties to secure your cable in place. Remember that you’ll have to fit a back panel on when you’re finished, so make sure nothing is sticking out too far.

If you’re using decorative cable extensions, the process is the same. Install any cable extensions to their matching cables (make sure not to mix up CPU and GPU power cables!) and route them to their normal locations (Images 43 and 50). Just know that since your cables are longer, you’ll have more excess to stash away out of sight.

Now onto CPU 8-pin power. This cable can be tricky, especially if your case is small or your cooler is big (or both). This cable will be the easiest to install with any top or rear fans removed, as its plug is usually located at the extreme top left corner of the motherboard (Image 49), possibly crowded by motherboard heatsinks. Feed the power cable through the cutout that’s closest to the connector. In a similar manner to the larger motherboard cable, reach in and pull it far enough through so you can turn it around towards the motherboard. Align the pins with the connector and push to latch until you hear the tab click into place. Plugging this cable in can be made easier if you’re using cable extensions: disconnect the extension from its PSU power cable and plug it in, from the front, into the CPU power plug. Once secured, feed the opposite end through the cutout and reconnect it to the PSU power cable. Pull extra cable length back through the back panel, creating a nice, tight bend when looking from the motherboard side (Image 53). Again, don’t pull too tight—make sure neither the socket or motherboard are bent or stressed. On the back side, use cable channels, velcro, and zip-ties to secure your cable in place. Stash excess cable length away underneath.

For both SATA and Molex power cables, a good tip is to feed the cable through the closest cutout or “the path of least resistance” for each device. Try to avoid cables laying on the bottom of the case, draping over other cables, or hanging in midair. The cleaner you route these now, the easier future upgrades and/or troubleshooting will be. If your case uses a built-in fan or RGB hub, chances are it’s powered by SATA or Molex power. In this case, the cables might not need to be fed into the front area of the case; they might all stay in the back or bottom, out of sight.

Even though the graphics card isn’t installed, route its power cables to about where they’ll be once the card is in. Most cases have a cutout on the bottom, below the graphics card, for graphics card power cables. Like how the motherboard and CPU power cables come out through the back side close to the plugs, GPU power cables usually come up through the floor for the cleanest look (Image 54). Check your GPU for the type (and the quantity) of cables required, and pull them up through the bottom, being sure to leave enough slack to plug them in later.

Image 54

Image 55

Spend some time cleaning up the back of your case (Image 55). Although this area won’t be visible, easy-to-follow cable paths can relieve future headaches when the time comes to upgrade—or troubleshoot a problem. Plus, you’ll need to actually get your back panel on without a massive bulge—now’s the time to avoid the future fuss!

With your cables installed, routed, and managed, use the four screws included with your PSU to secure it down (Image 56). Not all power supplies secure at the four corners exactly; follow the rear case cutout as a guide for where each of the four screws are supposed to go (Image 57). Keep the PSU power switch flipped off for now.

Image 56

Image 57

If you’re using 2.5-inch or 3.5-inch storage drives or 5.25-inch drive bays like DVD drives or CD burners, you’ll need two cables for each: SATA data and SATA power. The data cables plug into their matching ports on the motherboard, usually located near the bottom of the right edge. The power cables come directly from your PSU. Both are keyed and can only install one way. Although drive bay support is hit-or-miss on modern case options, most offer a variety of mounting locations for storage drives, including but not limited to the “basement,” near the cables, the back panel behind the motherboard (Image 58), or the internal panel next to the motherboard. It’s your choice. Secure your drive(s) with the screws included with the case, and make sure both cables are fully seated at both ends.

Now, finally, for the pièce de résistance, the GPU (Image 61)! Here’s how to install it:

• Remove PCIe slot covers installed where your GPU will go. Look for the highest-up “long” (16x) PCIe slot (Image 59), remove that cover, and the one, two, or three below it depending on your card’s thickness (Image 60). Some slot covers are secured with screws—don’t misplace these; you’ll need them to secure the GPU in a second. If your case has pop-out covers, locate the required screws from your motherboard accessories before continuing.

Image 59

Image 60

• Unlock the PCIe slot by pushing the tab towards the motherboard.
• Slot your GPU into the topmost PCIe 16x slot. Support the card with one hand, as the slot alone isn’t enough to keep it secured (Image 62). While you’re slotting the card in, make sure the tabs on the I/O plate slot into the thin gap between the case and the motherboard on the left side near the PCIe slot covers you just removed. When inserted correctly, the PCIe slot’s locking tab should click towards you when it engages fully.
• Secure the GPU’s I/O plate to the case with the screws that were holding in the slot covers. Keep the GPU supported with one hand while you do this (Image 63). To help prevent sag, it can help to ever so slightly push the card upwards while tightening down the screws to counteract the natural weight of the card.
• Plug in the GPU power cables (Image 64). Make sure the locking tab is on the correct side—these only go in one way. Triple check that these cables aren’t for CPU power (Image 43).

Image 62

Image 63

Image 64

We’re almost finished (Image 65). If you have fans you removed earlier, you can reinstall them now. Check previous cables, like USB, front panel, fans, and power cables, and make sure nothing got unplugged while you were installing other components. Check that your RAM is seated, check that your back panel fits, etc. Don’t put your front panel on just yet; we’ll test everything before we close up the case.

Image 65

Image 66

For the first power-on, I prefer to find a monitor, a keyboard, and a mouse so I can check that everything looks good in the BIOS menu. A computer’s UEFI, or BIOS, is the motherboard’s firmware—essentially its own core operating system—and is the interface you interact with to see all connected devices before/without installing an actual OS like Windows, Linux, etc. It controls boot drives, CPU clock speeds, memory settings, and can monitor core metrics. Note: modern motherboards support UEFI, with “BIOS” or “BIOS menu” coming to colloquially mean the same thing.

First, plug your keyboard and mouse into the USB ports on the back of your case, the ones connected directly to the motherboard. Plug your display in (via either HDMI or DisplayPort) to your GPU—this is important! Don’t make the (very common) mistake of plugging the display into the motherboard instead. Make sure your display is plugged into a wall outlet, too.

Plug the power cable into your PSU and into the wall. Flip ON the PSU power switch. Now, press the case power button. You should see activity within the case: fans should spin, and if you have RGB, some of it may light up (Image 66). Repeatedly press the DELETE key on your connected keyboard to enter the BIOS. Note: the DELETE key is how you enter the BIOS on most motherboards, but some others may use a function key like F11 or F12. Consult your motherboard manual to double check. You should see your motherboard logo on a splash screen followed by the BIOS menu.

The BIOS menu will display your CPU name, cores, and clock speed. Check that this looks like the one you installed. It will display CPU temp, too — make sure this temp is within operating spec for your chosen CPU. Consult your manual or online resources if you’re unsure. It will also display your installed RAM, and usually shows which channels are populated. Make sure this also matches what you installed. It’ll also show your RAM speeds, but note that these may look slower than you’d expect since you’ll eventually need to enable XMP (or equivalent, like EXPO or DOCP) to achieve full rated speeds. Next, check to see that the BIOS can see your installed boot drive—its name and size should match the one you installed. Finally, check that the BIOS can see all of your fans, and, while you’re at it, peek inside of the case to make sure all of your fans are actually spinning. If everything looks good, power off your PC by pressing and holding the power button.

Now what? Chances are, you’ll want to install Windows. The easiest installation is with an ISO on a USB drive. Find yourself a USB drive that’s larger than 8 GB and a friend with another computer. For Windows 10, follow these steps. For Windows 11, go here. Note: if you need to run Linux, everything should be prepped and ready to follow the instructions for your distro of choice.

Note: your graphics card might not show up in Task Manager or your display resolution might look funky until you install graphics drivers. Learn how to do that here.