A Tour Inside a Desktop PC

1
Inside the Case

Picture of the inside of a computer
Inside the Case. © ArmadniGeneral / en.wikipedia

Understanding how the many parts of a computer connect to each other inside your PC begins with the case, which physically houses most of the components.

  • Power Supply: The power supply connects to nearly every device in the PC to provide power. It is located at the rear of the case.
     
  • Drive Bays: The 5.25" and 3.5" drive bays house the many kinds of storage devices a computer might contain.
     
  • Expansion Slots: The expansion slots at the rear of the case are specially cut out so the peripherals connected to the motherboard can extend from the case for easy connection to external devices such as printers, monitors and other external devices.

2
The Motherboard

ASUS 970 Pro Gaming/Aura ATX DDR3 AM3 Motherboard
The Motherboard (ASUS 970). © Amazon.com / Asus

The motherboard is mounted inside the computer case and is securely attached via small screws through pre-drilled holes. All of the components in a computer connect to the motherboard in one way or another.

  • Expansion Cards: Motherboards usually contain a number of slots for internal peripheral cards like video cards and sound cards to connect to.
     
  • Back Panel Connectors: The back panel connectors extend out the back of the case for connection to external peripherals.
     
  • CPU & Memory Sockets: The CPU and memory connect directly to the motherboard via the CPU socket connector and memory slots.
     
  • Storage Drive Connectors: Storage devices are connected via cables to the motherboard. There are special connectors for floppy drives, optical drives and hard drives.

3
CPU and Memory

Picture of the CPU and memory sockets in a computer
CPU & Memory Sockets (ASUS 970). © Amazon.com / Asus

  • CPU: The CPU attaches directly to a CPU socket on the motherboard located inside the computer. The CPU is inserted into the socket pin-side-down and a small lever helps to secure it. In some pictures of a motherboard, you may see a large fan seated atop the CPU to help disperse heat.
     
  • Memory: Memory is installed in memory sockets located on the motherboard. These are easily locatable by looking for the small hinges on either side that lock the memory in place.

4
Storage Devices

Picture of a computer's storage devices and cables
Hard Disk Storage Devices & Cables.

Storage drives such as hard drives, optical drives and floppy drives all connect to the motherboard via cables and are mounted inside the computer.

  • SATA Cables: This example shows two hard disk drives that connect to the motherboard via SATA cables for fast hard drive access. Another kind of connection is the older PATA cable connection, but an example isn't shown in this image.
     
  • Power Connectors: Power from the power supply is delivered to both drives via cables that plug into the power port on the drives.

5
Peripheral Cards

Photo of an XFX AMD Radeon HD 5450 1GB GDDR3 VGA/DVI/HDMI Low Profile PCI-Express Video Card (ONXFX1PLS2)
XFX AMD Radeon HD 5450 Video Card. © XFX Inc.

Peripheral cards, such as the video card pictured, connect to compatible slots on the motherboard, inside the computer.

  • PCI Connector: This peripheral card was designed with a PCI connector and must be used in this type of slot on the motherboard.

Other types of peripheral cards include sound cards, wireless network cards, modems, and more. More and more functions typically found on peripheral cards, such as video and sound, are being integrated directly onto the motherboard to decrease costs.

6
External Peripherals

Picture of peripheral connections on a Dell Inspiron i3650-3756SLV computer
Motherboard Peripheral Connections (Dell Inspiron i3650-3756SLV). © Dell

Most external peripherals connect to the motherboard connectors that extend from the rear of the case.

  • USB Ports: Devices like mice, keyboards, digital cameras, scanners and printers often connect to the motherboard via the USB ports.
     
  • LAN Port: The LAN port is used to connect the PC to a local network or to high speed internet services.
     
  • VGA & HDMI Ports: On this motherboard, there's an HDMI port and a VGA port to provide video out to those types of display devices.
     
  • Audio Ports: Integrated line-out, microphone and line-in ports provide access to integrated audio, meaning there is no need for sound cards on this particular computer.
     
  • PS/2 Ports: Older keyboards and mice that aren't USB devices will connect to the computer via the PS/2 ports, which are not shown in this image above. Newer computers don't typically come with PS/2 connections.
     
  • Serial & Parallel Ports: Also not shown here are a serial port and parallel port to allow connections to printers and other external devices. Like mice and keyboards, these devices have basically been replaced by USB.