Introduction
In consumer electronics, a desktop computer (or desktop PC) is a multipurpose computer capable of more complex programs for use by a single user that electronics such as smartphones are not capable of. Desktop computers can be purchased as completed or in individual parts. Building a desktop PC allows the user the option to save money and get parts suited more for their personal needs. This means that unlike purchasing smartphones and tablets, the consumer will have to understand what parts of the desktop computer are necessary. Knowing what parts are necessary and what parts are are not is important when purchasing components for a computer. The essential parts of a computer are the Motherboard, CPU, RAM, Storage, GPU*, PSU, and Input/Output devices like the Monitor, Mouse, and Keyboard. Knowledge of these individual parts is important to making better purchasing decisions. Understanding what parts are necessary, and how they work will help consumers understand what to look for when purchasing these electrical components.
*(Note that while GPUs are not essential for using the internet and word programs, it is essential for graphically intensive programs such as video editing software and videogames. Additional information about graphics processing is located in the GPU section)
Discussion
Motherboard
In desktop PCs, motherboards are a central component in computer function that allow all the additional electrical components to work and communicate together. Similar to the way the nervous system works in the human body, motherboards are the bridge between all computer components (Kauer). They are essentially circuit boards, thin carbon fiber printed sheets with copper wiring laminated on, and connectors installed so that other electrical components can be plugged into the motherboard, completing a circuit. This allows the parts to communicate with each other and function. It is responsible for managing power and communication between all additional parts.
Like any electrical device, there are many differences in motherboards. The main differences that affect users are size and chip socket compatibility. Today, the most common sizes are Mini-ITX, Micro-ATX, and ATX. Mini-ITX motherboards are 17cm x 17cm in size and are more popular for smaller computer builds. Mini-ITX motherboards offer the smallest size of the three options but have limited expansion slots for future upgrades. Micro-ATX motherboards are more in the middle ground. Sizing in at 9.6in x 9.6in or smaller, micro-ATX motherboards have more room for expansion slots than a Mini-ITX but still have limited slots when compared to an ATX motherboard. On the other side of the spectrum, ATX motherboards are the most popular size measuring 12in x 9.6in. ATX motherboards include multiple slots for installing additional computer components.
The other big difference between motherboards is the chip socket compatibility. Socket compatibility determines which brand of CPU can be installed on that motherboard. The main CPU brands are Intel and AMD. In addition to this basic compatibility, each manufacturer also produces different sized CPUs within their brand. For example, Intel has produced both an 1155 and 1150 CPU architecture. Both the 1155 and 1155 CPU sizes require motherboards to be made specifically for that type of CPU socket. If a CPU is incompatible with the motherboard, it can result in physical breakage of the CPU and Motherboard if installation is attempted.
CPU
In desktop PCs, the CPU, or Central Processing Unit, is the main component in a computer and the component that runs the processes in a computer. It is commonly called the brains of a computer because it is responsible for all the decisions made by the computer (“GCSE Bitesize: Central Processing Unit”). CPUs take input from programs or other input devices on the computer and run the specified list of instructions given by each one. Those instructions are a step by step process on how to do a desired task. The CPU interprets the instructions, generates some sort of output, and sends the output to the appropriate output device. An example of this is a basic calculator program: The CPU takes the input commands of what mathematical function should be done from the calculator, follows the instructions of the calculator program to complete the function, creates the output, and then sends the answer back out to the calculator program.
Not all CPUs are created equal. There is a wide range of difference in speed, performance, and load the CPU can handle depending on the number of cores included and CPU brand. Each core in a CPU can handle a certain amount of work at a time. This work is typically measured in threads or processes. Processes are essentially programs being run by the CPU, such as the calculator program described above. More intensive processes can have multiple threads, which are smaller sections of the processes that do different things. By having more cores, the computer can run more processes simultaneously without sacrificing speed and performance. The two main CPU brands, referenced in the above motherboard section, are AMD and Intel. AMD tends to have less efficient cores in their CPU chips but includes more of them that work in pairs. It is common to see 6 or 8 cores in an AMD CPU. Intel focuses on having extremely efficient cores in their CPUs. 4 core CPUs are the mainstream option for Intel series chipsets. If a CPU with too few cores is selected for a computer there will be significant and noticeable performance reductions, such as painfully slow startup and run times. Choosing a CPU with more cores than necessary will result in a higher cost than necessary, as the more efficient and powerful CPUs which have more cores cost more.
When building a computer, it is generally advised to choose the desired CPU as one of the first components as it is the core of the computer and other parts may rely on the style and brand of CPU. For example, as mentioned above in the Motherboard section of the document, CPUs all have a specific socket size. Generally, choosing the motherboard that is compatible to the CPU instead of the CPU that is compatible with the motherboard is due to the importance of the CPU. The socket size is an important factor due to the consequences of not taking it into account. Breaking components such as the motherboard or CPU can be costly mistakes, and if improper installation is attempted breakage is almost always guaranteed. CPUs also can play a minor role in graphics processing. More information on this is included in the GPU section of the document.
RAM
In desktop PCs, RAM, or Random Access Memory, is a type of short term memory storage for data that is actively being used by any computer. An example of data that is actively being used on a computer is a program or application that is running, such as games, web browsers, and desktop applications. One function of RAM is to make the process of reading from and writing to a location in a computer’s storage the same amount of time no matter where in the storage the information being read or written to is located. This is so the time it takes to read information from an external storage port is the same as the time it takes to write to the internal storage on the PC. Another function of RAM is to save unsaved work, for example if there is an unsaved word document open on the PC, the information in the document is saved in RAM. Typically, RAM is a volatile type of memory, meaning that it needs power to store information, so if there is an unsaved word document open on a computer and the computer loses power, it will lose the document. There are some forms of RAM storage that are nonvolatile, meaning it does not need power to store information. The size of RAM is measured in gigabytes (GB), the amount of GB needed depends on what the PC is used for. For a work or school desktop that will be used for reading emails and writing documents 4GB would be plenty of RAM. For a PC that is used for programming, casual gaming, and editing as a few examples would need a larger size of RAM: around 8-10 GB. More advanced programs like simulation software, or gaming with optimal graphics and minimal latency could require higher sizes of RAM depending on the simulation software or the game. RAM is purchased in sticks, the type or amount of sticks depends on the motherboard (the motherboard is where the RAM is installed on the computer), for example if 16GB of RAM were desired one type of motherboard could hold one stick that is 16GB, and another could hold 4 sticks that are 4GB.
Storage
In desktop PCs, storage is a form of long term memory used to save and store digital data. Data from storage is sent to the CPU to be used and manipulated by the computer and user. Storage is nonvolatile, which means that information will be stored even if a computer does not have power. Storage is measured in GB but can be large enough to be measured in terabytes (TB).
Storage comes in two forms, HDD (shown left) and SSD. HDDs, or hard disc drives, use magnetic storage on a spinning disc to store and retrieve data. HDDs usually have more storage space than SSDs and are usually measured in TB. SSDs, or solid-state drives, use integrated circuits to store data. SSD’s are a newer technology and are typically measured in GB but can be large enough to be measured in TB. SDDs are more expensive than HDDs per GB and have faster read and write speeds than HDDs, allowing the computer to turn on, copy or move data, and run applications faster than HDDs. Another advantage of SSD is that they are more resilient than HDD. This means that accidental bumps while the computer is turned on can do damage to an HDD, but not an SSD.
GPU
In desktop PCs, the GPU, or Graphics Processing Unit, is a standalone component of computers responsible for display functionality and any calculations involved in creating images. While the GPU is not a required component of computer use, it can drastically improve the use of any visual media. They are often required to run video games on your computer if that is a desired capability. They are specialized to render images, create animation, and video display for the computer (“Definition of: GPU”). Without a GPU, those tasks are allocated to the CPU and take much larger amounts of time and resources to complete. Nowadays, there are often integrated GPUs into CPUs, but they are required to share memory with the CPU and are not as effective as a separate GPU.
The GPU accomplishes image processing so well through specialized hardware development. The reason GPUs are better at image processing and video interfacing than CPUs with integrated graphics is due to the internal circuitry installed in them. The internal circuits of GPUs are specifically designed to allow for faster completion of specific style tasks, usually repetitive in nature. By doing this they are significantly slower at other functions, which is why GPUs alone cannot replace CPUs. They also include their own memory, called Video-RAM, or VRAM. By having VRAM, GPUs have their own dedicated memory and do not need to share resources with the CPU. This allows the GPU to continuously be working at its specifications even if the CPU and RAM are heavily loaded.
PSU
In desktop PCs, PSUs, or power supply units, are what provide power to the entire computer. The power input for a PC (in America) is a 120 volt AC power source. The components in a computer use low voltage DC power as their power supply, so the PSU converts the high voltage AC power to low voltage DC power. Upon startup, the PSU sends a signal to the motherboard which is used to check if the DC voltages are safe for the computer to power up. Most power supplies automatically adapt to the input voltage, but some have a manual switch for selecting input voltage. The PSU is controlled by the motherboard sending it signals that tell it when and how to convert power after startup.
Monitor, Mouse, & Keyboard (I/O Devices)
These accessories are often not considered when thinking about computer parts, but are essential for basic computer usability. These components are based heavily on the needs and wants of the user purchasing them. For example, one user may be interested in competitive gaming. For this users, having a high refresh-rate monitor and a precision mouse are necessary. For a user that is using the computer for photography, having a monitor with correct color reproduction is necessary. Knowing what kind of I/O Devices will suit your needs is important to consider when building a computer.
Monitors
In desktop PCs, monitors are an output device that display images produced by the GPU or CPU. Monitor screens can come in a variety of resolutions, sizes, and designs. A monitor’s resolution correlates with how detailed and how much can be shown on the screen at one time. Measured in PPI, the resolution of a screen is how many pixels per inch (measured diagonally) make up the display. Popular resolutions include 1280 × 720, 1920 × 1080, 2560 × 1440, and 3840 × 2160. These, and other resolutions generally stick to the 16:9 ratio. Monitors that follow a ratio of 21:9 or 16:10 are known as widescreen displays. The size of a monitor does not directly correlate with the resolution of the monitor but can have an effect. If a monitor is 27 inches big but the display is only 720p, then the DPI will be too low, and the individual pixels of the display will be too noticeable. Displays can also utilize different panel technologies. The most common technologies used are IPS and TN. IPS tend to have better color reproduction and greater viewing angles while TN panels tend to have higher refresh rates and be cheaper.
Mouse/Mice
In desktop PCs, computer mice are an input device that utilize an optical or laser sensor and commonly contain two or more buttons and a scroll wheel. Computer mice are designed to control a digital cursor by translating the movement of the mouse into movement of the cursor. This interaction is measured in DPI/PPI which is the number of pixels navigated by the cursor per inch of movement measured by the sensor on the mouse. Most PC mice consist of two buttons, often referred to as right and left mouse buttons. These buttons allow the user to interact with clickable buttons. Mice generally have a scroll wheel that helps users navigate webpages and documents by allowing the user to free scroll without using the scroll bar in the document. Computer mice generally connect to the computer through USB, while some older mice may use a PS2 port.
Keyboards
In desktop PCs, keyboards are a type of input device that contain varying number of keys that correspond to alphanumeric symbols and other actions. Keyboards, like mice, interface with the motherboard. This is either done through USB or PS2 ports. Keyboards vary wildly in size, layout, and features. These variances are based on a full-sized keyboard, which is the full QWERTY + Function Keys + Arrow Keys + Number Pad. The term ‘tenkeyless’ is also used to reference keyboards without number pads.
Conclusion
These individual electronic components work together to form a fully functioning Desktop Computer. The Motherboard, CPU, RAM, Storage, GPU, PSU, and I/O devices are all essential components for a fully functioning desktop PC. Knowing that these are the essential parts to a computer, the consumer can make a more informed decision when purchasing these parts. By knowing how these parts work individually, and with each other, the consumer can also better appreciate how the computer they have built works.
Glossary
- Byte: In computers, a byte is a group of 8 bits each of which can be 0 or 1, which is used for storage. A gigabyte (GB) is one billion (10^9) bytes, a terabyte (TB) is one trillion (10^12) bytes.
- Clicking, Click on: In computers, clicking refers to the activation of a physical switch or key (usually located on the computer mouse) in order to interact with digital buttons.
- CPU: Central Processing Unit
- Data: In computers, data is any form of information that can be used or stored in the computer.
- DPI/PPI: In computer mice, DPI, or Dots Per Inch, refers to the amount of pixels a cursor will cover per inch of mouse movement. PPI, or Pixels Per Inch has the same definition and can be used interchangeable with DPI.
- GPU: Graphics Processing Unit
- I/O: Input/Output. Ways of giving information into a system or receiving it back out.
- PS2: In computers, “PSU is an electronic receptacle found on computers” that is designed for keyboards and mice to ensure that there were no conflicts with other inputs. (wiseGEEK).
- The PS2 port has generally been replaced by USB ports, but can still be found on some motherboards.
- RAM: Random Access Memory
- USB: In computers, USB (Universal Serial Bus) is a connection port that connects external devices to the computer.
- VRAM: Short for Video-RAM. It is the same as RAM (see above), only included in the GPU (Graphics Processing Unit)
Works Cited
“Chapter 3: Application Software.” Uwf.edu, University of Western Florida, uwf.edu/clemley/cgs1570w/notes/Concepts-3.htm.
“Definition of: GPU.” GPU Definition from PC Magazine Encyclopedia, PCMag,
www.pcmag.com/encyclopedia/term/43886/gpu.
Fisher, Tim. “All About the Power Supply Unit (PSU).” Lifewire, Lifewire, 8 July 2017,
www.lifewire.com/power-supply-unit-2618158.
“GCSE Bitesize: Central Processing Unit.” BBC, BBC, www.bbc.co.uk/schools/gcsebitesize/ict/hardware/0inputandoutputdevicesrev3.shtml.
Kauer, Harjeet. “Computer Components for Idiots.” Singapore Travel Guide, Street Directory, www.streetdirectory.com/travel_guide/116131/computers/computer_components_for_idiots.html.
Kayne, R., and Niki Foster. “What Is a PS/2 Port?” WiseGEEK, Conjecture Corporation, 11 November 2017, www.wisegeek.org/what-is-a-ps2-port.htm.
Krewell, Kevin. “What’s the Difference Between a CPU and a GPU?” The Official NVIDIA Blog, NVIDIA, 9 August 2017, blogs.nvidia.com/blog/2009/12/16/whats-the-difference-between-a-cpu-and-a-gpu/.
“Mechanical Keyboard Terminology.” The Ultimate Mechanical Keyboard Catalog, Mechanicalkeyboards.com, mechanicalkeyboards.com/terms.php?t=Tenkeyless%2B%28TKL%29.
Rouse, Margret, and Dave Raffo. “What Is Data Storage? – Definition from
WhatIs.com.”SearchStorage, Tech Target, 21 September 2005, searchstorage.techtarget.com/definition/storage.
Rouse, Margaret, and Rodney Brown. “What Is RAM (Random Access Memory)? – Definition from WhatIs.com.” SearchStorage, Tech Target, searchstorage.techtarget.com/definition/RAM-random-access-memory.
Smith. “A Guide to Motherboard Sizes.” Bright Hub, Bright Hub, 11 March 2010,
www.brighthub.com/computing/hardware/articles/66050.aspx.
“What Is a Motherboard?” Computer Hope, Computer Hope, 30 Oct. 2017, www.computerhope.com/jargon/m/mothboar.htm.