Install a processor, apply thermal paste, and mount the heatsink/cooler correctly
Before opening the case, shut down the system, switch off the PSU, and unplug the power cable. Press the power button once after unplugging to drain residual charge.
Prevent ESD. A static discharge you can't even feel can kill a CPU. Wear an anti-static wrist strap clipped to bare chassis metal, or self-ground by touching the metal case before handling the chip. Handle the CPU by its edges, never the contacts/pins, and set it on an anti-static mat — not on carpet or a plastic bag's outside.
These precautions come first, before any of the steps below. CompTIA A+ tests ESD-prevention tools and safe power-down as their own objective.
LGA (Land Grid Array) Pins are on the motherboard socket; the CPU has flat contacts. Used by Intel. Drop the chip in with zero force. Never press or drag. Bending a socket pin is often irreparable.
PGA (Pin Grid Array) Pins are on the CPU itself; the socket has holes. Used by AMD (AM4). Lower gently and press straight down with the ZIF lever. Bent pins on the chip are possible but sometimes repairable.
This lab covers LGA procedure, which is the dominant A+ exam scenario. The orientation rule (pin-1 triangle) applies to both types.
Every CPU has a small gold triangle on one corner. The socket has a matching marker (triangle, notch, or arrow). These must align before seating.
Paste fills microscopic air gaps between the CPU heat spreader and the cooler base.
CPU_FAN The only correct header for the CPU cooler fan. The motherboard monitors RPM and ramps fan speed based on CPU temperature. A missing connection triggers thermal protection and POST warnings.
SYS_FAN / CHA_FAN General case/chassis fans. These headers do NOT control or report CPU thermal status. Plugging the CPU cooler here leaves the CPU unmonitored and potentially uncontrolled.
Most boards label the header directly on the PCB silk-screen. It is a 4-pin PWM connector.
LGA sockets use a hinged metal load plate held by a retention lever. Push the lever down and outward to release, then lift it to vertical. Raise the load plate fully so the socket contacts are exposed. Do not touch the socket pins.
The socket diagram below shows the pin-1 marker in the bottom-left corner. Select the orientation that places the CPU's gold triangle at the matching socket marker.
The CPU gold triangle must match the socket's pin-1 marker (gold triangle, bottom-left above). Select the CPU orientation:
Apply thermal compound to the center of the CPU's integrated heat spreader (IHS). The cooler pressure will spread it. Select the correct amount:
Lower the cooler straight onto the CPU. Tighten the four mounting screws in a cross (diagonal) pattern. Do not tighten one corner fully first, as uneven pressure bows the cooler and leaves hot spots. Tighten gradually in a star/X pattern until all four are snug.
The CPU cooler fan must connect to the motherboard's CPU_FAN header so the board can monitor RPM and ramp speed based on processor temperature. Select where you will plug the fan connector: