How to Build a Gaming PC: Step-by-Step Computer Building Walkthrough

By Published March 29, 2016 at 2:30 pm

Build the System in the Case

Time to migrate everything. This part's pretty easy.

We're going to go backwards on a few of our recent steps, but can salvage almost all of the work and migrate the components into the case. The steps for re-installing the cabling and video card will be more-or-less identical to what was already done, so you've effectively already completed your first PC build -- we're just making it more conventionally acceptable, now.

  1. Flip the power switch on the PSU to toggle power and shut-down the system (set to '0'). Leave the PSU in this '0' state (unless the PSU's switch will be obstructed by the case – some mITX cases will do this).

  2. Remove all the power cables.

  3. Remove the video card by pressing down on the PCI-e tab, then removing the card itself. This should not require any real force.

  4. Leave the CPU, cooler, and RAM installed. Leave the CPU fan cable socketed.



We're now untethered and ready to move the motherboard (and the pre-mounted cooler, CPU, and RAM) into the case.

Installing a PSU

  1. Connect all necessary modular cables before mounting the PSU.

  2. Install the power supply. This normally is as easy as using four screws (hex-heads, Phillips driver). The PSU fan or grill (if it's passively cooled) should be facing the outside of the case if an external-facing mesh/grill is present.

  3. If your case uses a PSU shroud, there's a good chance it has a custom plate/bracket of some kind. Check the manual.

If using a non-modular PSU, begin the cable management process by routing necessary cables through the rear of the motherboard tray (so that they will be in the back compartment of the case, not the main compartment). Stuff unneeded cables in the bottom corner where they won't obstruct fans or accumulate dust.

Install the I/O Shield & Motherboard


The I/O shield is easy to forget, but also technically unnecessary. If you want the I/O shield (mostly used to prevent stuff from falling into the back of the case – like a USB key, which could short something), be sure to socket the I/O shield into the back of the case prior to installing the motherboard. The I/O shield's holes will align with the motherboard's rear I/O.

  1. Check that stand-offs are present in the case. These are often brass-colored, but are sometimes the color of the case (black). If they are not installed, grab the hex-headed stand-offs and mount them in the slots appropriate for your motherboard's form factor (ATX, mATX, etc.). Stand-offs are used to prevent a direct short to the motherboard, which will happen if the board touches the steel tray of the case.

  2. Mount the I/O shield.

  3. Drop the motherboard into the case gently. Do not lift by the CPU cooler that we pre-installed.

  4. Align motherboard on stand-offs. Ensure all stand-offs are present. Align motherboard with I/O shield.

  5. Use appropriate MB screws to mount the board. Do not skip any screws. This will help keep things grounded and prevent direct shorts or flexing in the future.

Install Storage Devices (SSD, HDD, M.2 SSD, PCI-e SSD, etc.)


Locate the SSD or HDD cages and sleds. Decide if you'd like to install the SSD in any special rear-of-tray slots (check case manual for options).

This should only take about four screws. Install them, expose the SSD/HDD cable connectors to the SATA power and SATA data cables.

Power & Front Panel Cables


We'll do cable management after making sure everything still works. Let's repeat that process we did earlier.

  1. Connect the 24-pin power cable to the 24-pin connector on the motherboard (right side, if assuming standard motherboard orientation).

  2. Connect the 8-pin power cable to the 8-pin connector on the motherboard (near the CPU).

  3. Double-check that CPU_FAN is connected.

  4. Connect SATA data cable to the motherboard. Make sure that you are using the correct slot (boards with large banks of SATA headers may have multiple controllers, and some are better-suited for SSDs). Check manual for this.

  5. Connect USB3.0 front panel header, if present, to motherboard. Do this before mounting the video card as it is easier. Be careful not to bend the pins on the board-side. Line-up the notch on the cable with the gap in the housing.

  6. Connect front-panel cables to motherboard. These are:

  • PWR_SW (sometimes PWR_BTN)




  • PC speaker optional

Make sure the text is facing outward. If the PWR_SW is in the top-right position on the FPC, install the cable so that the text is readable from the outside. This isn't always required, depending on which cable it is and how it's wired, but will ensure that cables with +/- sensitivities are functional.


The position for these cables changes on a per-board basis. Check the legend printed on the board or in the manual for reference.

Finally, connect these cables:

  1. Case fans to 3-pin and 4-pin PWM slots on the board. If using a case like the NZXT H440 or Corsair 600C, a fan hub may be present for easier management. Plug fans into this instead, if available, and then power the hub with a 4-pin MOLEX or SATA power cable from the PSU.

  2. HD Audio from front panel (3.5mm audio). Normally far left of motherboard, near the expansion slots.

  3. USB2.0 headers from front panel. Normally near the FPC / bottom middle of board.

Installing the Video Card (last)


Install the video card using the same steps you did earlier, but this time, remove the expansion slot covers that block the relevant PCI-e slot. Tighten both screws if using a dual-slot card; this will help reduce sag.

Connect power to the card.

Boot-Up & Initial Setup


Time to boot. You can leave the side panels off at this time. Use the power button on the case to fire the boot. If boot fails, double-check first that the FPC cables are connected to the correct pins. If your system was validated as functional before installing it into the case, there's a good chance that any failure to boot is a result of incorrect wiring or missed power cables. There's always the chance of ESD – but that is rare and unlikely if using our previously-stated measures to limit ESD risk. Check all the cables. Follow our troubleshooting guide if it's still a no-go.

Once booted, head into BIOS and configure to your contentedness. We'd advise against overclocking at this time. Get a platform / environment setup before playing around with that. Check that memory is set to the desired XMP or speed, check that the boot order is correct (will you install the OS from a USB key? Set that first), check that the SATA mode is AHCI or NVMe (or configure RAID, as appropriate) depending on your storage device.

At this point, everything's working. It's a good time to power-down and do some more advanced cable management, if you have a thing for cleanliness. Use cable ties and zip ties to pull things out of the way and close-up the side panels. If you have issues closing the right side panel (rear of tray is bulging with cables), move them as best you can, then lie the case on its opposing side and use gravity in your favor. This works wonders.

Once good, boot to the media for Windows, Linux, or other OS install. Follow instructions and install to the device you wish to be the primary drive. We'd recommend Ninite for post-install bulk downloads.

As always, questions in the comments below or on our forums for in-depth help. Our PC build guides contain updated lists with compatible build options.

Editorial, Host: Steve “Lelldorianx” Burke
Video Production: Andrew “ColossalCake” Coleman

Resources and links to follow.

Last modified on March 29, 2016 at 2:30 pm
Steve Burke

Steve started GamersNexus back when it was just a cool name, and now it's grown into an expansive website with an overwhelming amount of features. He recalls his first difficult decision with GN's direction: "I didn't know whether or not I wanted 'Gamers' to have a possessive apostrophe -- I mean, grammatically it should, but I didn't like it in the name. It was ugly. I also had people who were typing apostrophes into the address bar - sigh. It made sense to just leave it as 'Gamers.'"

First world problems, Steve. First world problems.

We moderate comments on a ~24~48 hour cycle. There will be some delay after submitting a comment.


  VigLink badge