The system unit houses the primary components that perform operations and calculations for a computer. It includes the motherboard, CPU, RAM, and other parts housed within a case. Some key components are the motherboard, CPU, RAM, hard drive, power supply, fans, optical drives, video card, and ports. The system unit contains the main parts that control and store data for the computer.

1. What Does System Unit Mean?
• A system unit is part of a computer that houses the
primary devices that perform operations and produce
results for complex calculations. It includes the
motherboard, CPU, RAM, and other components, as
well as the case in which these devices are housed.
This unit performs the majority of the functions that a
computer is required to do.

2. Components of System Unit
• Some of the components in the system unit are; random access
memory (RAM), compact disk read-only memory (CD-ROM), hard
disk, motherboard, fan, processor or central processing unit
(CPU), power supply, and floppy disk drive.
•
• The system unit also has other components, such as a universal
serial bus (USB) port, power button, cables, video, and sound
card.

3. Main components of the system unit.
• 1. Motherboard
• The motherboard is the main internal hardware component of the system unit. This board is called the
"motherboard" because it has all the connectors that connect to the other hardware components of the
computer system.

4. 2. CPU or PROCESSOR
• 2. CPU or Processor
• The CPU is the hardware component responsible for all operations performed in the computer system,
which is why most computer users call it the brain of the computer, which is fixed on the motherboard
through a slot.

5. 3. RAM
• 3. RAM (Random Access Memory)
• RAM is the main memory of a computer system, and its main function is to temporarily store data.

6. 4. Hard Drive
• 4. Hard Drive
• The main storage device of a computer system is a hard disk or hard disk drive. Unlike RAM, which
temporarily stores data, the main function of a hard drive is to permanently store information, files, and
other documents, and also allows data to be retrieved, but it is non-volatile (data will not be lost when the
computer is shut down).

7. 5. CPU Fan and Heat Sinks
• 5. CPU Fan and Heat Sinks
• Basically, computers come with two fans in the system unit or chassis, sometimes three. One CPU fan, one
case fan and sometimes, one hard drive fan. A manufacturer can also decide to put in more than one CPU
fan or case fan. During operations by the computer the CPU produces a lot of heat and heat could always
cause damage to your computer, that is why the CPU fan is put in place to keep the CPU under the required
temperature.

8. 6. CD-ROMs/DVD rom drives
• 6. CD-ROM/DVD-ROM drives
• Compact disc(CD) and digital versatile disc (DVDs) are storage devices onto which a certain amount of audio
files, data, and other computer files can be stored.

9. 7. PSU or Power Supply Unit
• 7. PSU or Power Supply Unit
• Just as any electronic device needs electrical power to function, so as the system unit’s components. But the
components do not work with the power from your wall socket so the computer power supply unit receives
the alternating current (AC) and converts it to a controlled direct current (DC) for the components to
function.

10. 8. Floppy disk drive
• 8. Floppy disk drive
• This is an internal hardware component in the system unit positioned closer to the CD-ROM drive and its
main function is to read and write from or on a floppy disk or diskette.

11. 9. SATA Serial Advance Technology
Attachment
• 9. SATA cable is mainly used to connect the internal hard drive to the computer motherboard. It can also be
used to connect a hard drive to a hard drive, and connect ATA and ATAPI devices to the computer
motherboard, and connect to an external computer.

12. 10. Video Card
• 10. A video Card is also called a video controller and appears as a circuit board to fit on motherboard. The
video card contains electronic circuits having GPU, visual processing units, heat sink, video BIOS, video
memory, RAMDAC, video graphics array, digital visual interface, HDMI, and display port.

13. 11. Computer Case
• 11. A computer case, also known as a computer chassis, tower, system unit, or cabinet, is the enclosure that
contains most of the components of a personal computer (usually excluding the display, keyboard, and
mouse). Cases are usually constructed from steel (often SECC—steel, electro-galvanized, cold-rolled, coil),
aluminum, and plastic.