Inside the PC: CPU, RAM, motherboard & power supply

The four parts that make a PC “go”

Open any desktop computer and, past the cables, you will always find the same core team working together. The CPU does the thinking, the RAM holds the work you are doing right now, the motherboard connects everything, and the power supply feeds the whole machine. Learn these four and the inside of a PC stops being a mystery.

The CPU: the brain

The CPU (Central Processing Unit) carries out the instructions that make programs run. Three words describe it on a spec sheet. Cores are independent workers inside one chip; a 4-core CPU can juggle four jobs at once, so more cores help with multitasking. Clock speed, measured in gigahertz (GHz), is how many cycles of work it does per second, so higher is generally faster. The socket is the shaped slot on the motherboard the CPU drops into. The socket must match the CPU exactly — an Intel chip will not fit an AMD socket, and vice versa.

The CPU runs hot, so it always sits under a heatsink and fan (or a liquid cooler). Never run a PC with that cooler removed.

RAM: the desk you work on

RAM (Random Access Memory) is fast, short-term memory. Think of it as your desk: the bigger the desk, the more papers (programs and files) you can have open at once. RAM is volatile, which means it is wiped the moment power is lost — that is why unsaved work vanishes in a crash. Capacity is measured in gigabytes (GB); 8 GB is a sensible minimum and 16 GB is comfortable today. Desktop RAM comes on DIMM modules; laptops use the smaller SODIMM. Installing modules in matched pairs enables dual-channel, which lets the CPU reach memory faster.

The motherboard: the connector of everything

The motherboard is the big circuit board everything else plugs into. Its chipset manages the traffic between the CPU, memory, and devices. It carries slots (the CPU socket, RAM slots, and PCIe slots for cards like a graphics card) and connectors (for storage, USB, and front-panel buttons). Boards come in form factors — sizes that decide how much fits and which case they need. ATX is the full-size standard, Micro-ATX is smaller, and Mini-ITX (mITX) is the tiny one.

The power supply: feed it safely

The power supply unit (PSU) converts wall power into the steady low voltages the parts need. Its wattage rating (for example 550 W) is the most power it can deliver — a gaming PC with a hungry CPU and GPU needs more than an office PC. The PSU connects with a large 24-pin plug to the board, a CPU power plug, and SATA/PCIe plugs for drives and cards. Safety rule: never open a PSU. Its capacitors can hold a dangerous charge even when unplugged. A faulty PSU is replaced as a whole sealed unit, never repaired.

See your own hardware

You do not need to open the case to read your specs. Open PowerShell and ask Windows directly:

Get-CimInstance Win32_Processor | Select-Object Name, NumberOfCores, MaxClockSpeed
Get-CimInstance Win32_PhysicalMemory | Select-Object Capacity, Speed

Or use the classic one-liner that prints a full system report:

systeminfo

Your task

On your own PC, run the two Get-CimInstance commands above. Write down your CPU name, its number of cores, its clock speed in GHz, and your total RAM in GB. Then state in one sentence whether your machine uses DIMM or SODIMM memory and how you can tell (desktop versus laptop).