How to Assemble a Desktop Computer
Assemble a custom desktop computer from components including the CPU, cooler, RAM, motherboard, storage, power supply, and GPU inside a standard PC case.
- Read the tools, materials, safety notes, and steps below for free.
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🧰 Required Tools & Equipment
- ✓ #2 Phillips head screwdriver
- ✓ #1 Phillips head screwdriver
- ✓ Anti-static wrist strap
- ✓ Small wire snips
- ✓ Flashlight or headlamp
📦 Materials & Supplies
- ✓ Computer case with standoffs and screws
- ✓ Motherboard
- ✓ CPU (Central Processing Unit)
- ✓ RAM modules (DDR4 or DDR5)
- ✓ M.2 NVMe SSD
- ✓ Power Supply Unit (PSU) with modular cables
- ✓ CPU Cooler with thermal paste
- ✓ Graphics Card (GPU)
⚠️ Safety Checkpoints & Warnings
- • Ground yourself regularly against bare metal or wear an anti-static strap to prevent electrostatic discharge.
- • Ensure the power supply is completely unplugged from the wall outlet until assembly is fully complete.
- • Handle the CPU strictly by its edges to avoid bending fragile pins or contaminating the thermal contact surface.
📋 Step-by-Step Guide (6 Steps)
Prepare Motherboard, CPU, and Storage
Place the motherboard on top of its non-conductive cardboard box. Lift the CPU socket retention arm, align the gold triangle on the CPU corner with the socket marker, and gently drop the CPU straight into the socket without forcing it. Lower the retention arm to lock it in place, then install the M.2 NVMe SSD into the primary slot and secure it with its tiny screw.
- • CPU socket lever is fully locked down underneath the metal retention tab.
- • M.2 SSD lies completely flat against its standoff with the mounting screw snug.
- • Forcing the CPU down with finger pressure instead of letting it seat by gravity.
- • Placing the motherboard on the outside of an anti-static bag (which is conductive).
Install RAM and CPU Cooler
Open the locking clips on RAM slots 2 and 4 (check manual for dual-channel priority). Align the notch on each RAM stick with the socket ridge and press firmly on both ends until the clips snap shut with an audible click. Mount the CPU cooler bracket, apply a pea-sized dot of thermal paste to the CPU center if not pre-applied, and screw the cooler down evenly in a cross pattern.
- • Both RAM retention clips are fully upright and flush against the DIMM sides.
- • CPU cooler is firmly centered over the CPU with fan cable plugged into the CPU_FAN header.
- • Forgetting to peel off the transparent protective plastic sticker from the cooler base.
- • Inserting RAM modules in adjacent slots instead of alternate dual-channel slots.
Install Power Supply and Prepare Case
Remove both side panels of the PC case. Orient the Power Supply Unit (PSU) with its intake fan facing the case ventilation filter, slide it into the lower compartment, and secure it with four case screws from the rear. Install motherboard standoffs inside the case corresponding exactly to the mounting holes on your motherboard size (ATX/mATX).
- • Four PSU screws secured flush on the rear chassis panel.
- • Standoffs installed only in positions matching motherboard mounting holes.
- • Leaving an extra standoff installed where the motherboard has no hole, risking a short circuit.
- • Facing the PSU fan directly against a solid metal wall rather than the intake vent.
Mount Motherboard in Case and Connect Front Panel
Snap the rear I/O shield into the case cut-out if not integrated on the motherboard. Gently angle the motherboard into the chassis, matching the rear ports to the I/O cutout, then lower it onto the standoffs. Secure with screws starting from the center standoff, then connect the case front-panel connectors (power switch, reset, front audio, USB headers) to the bottom pins of the motherboard.
- • Rear motherboard ports poke cleanly through the I/O shield with no grounding prongs stuck inside ports.
- • All motherboard standoff screws are snug and secure.
- • Allowing metal spring prongs from the I/O shield to insert into HDMI or USB ports during insertion.
- • Connecting the front panel Power Switch (PWR_SW) to the wrong motherboard pin.
Route Power Cables and Connect Power
Route the 24-pin ATX power cable from behind the motherboard tray and plug it into the right edge of the board until the clip latches. Route the 8-pin (or 4+4-pin) CPU EPS power cable to the top-left corner and plug it in firmly. Connect SATA power cables to any 2.5-inch/3.5-inch drives, and ensure case fan headers are connected to SYS_FAN or CHA_FAN pins on the motherboard.
- • 24-pin ATX power clip completely hooked over the motherboard socket ledge with no gap.
- • CPU EPS cable seated tightly into top-left connector without straining.
- • Accidentally forcing a PCIe 6+2-pin cable into the CPU 8-pin connector (different pin pinouts/shapes).
- • Failing to press the 24-pin main connector fully until the retaining clip locks.
Install Graphics Card (GPU) and First Boot Test
Remove the top 2-3 PCIe slot covers from the rear of the case matching your GPU thickness. Open the PCIe slot lock on the top x16 slot, align the GPU connector, and press firmly until the slot lock clicks shut. Secure the GPU bracket with thumb screws to the case frame, attach the dedicated PCIe power cables, connect your monitor to the GPU port (not the motherboard), and power on to verify BIOS boot.
- • PCIe slot retention tab snapped completely closed over the GPU contact finger.
- • Monitor displays the motherboard manufacturer splash screen or BIOS setup page.
- • Plugging the monitor's HDMI or DisplayPort cable into the motherboard rear instead of the dedicated GPU.
- • Daisy-chaining a single split PCIe cable for a high-wattage graphics card instead of running separate individual cables.
Credit: inspired by an original tutorial by Linus Tech Tips — watch the original on YouTube.
Don’t have everything?
- No Anti-static wrist strap? Frequently touch the unpainted metal chassis of the plugged-in (switched off) PSU
- No Small wire snips? Standard household scissors (cut cable ties carefully without nicking wires)