module 02
Introduction to computer hardware
CPU cache and overclocking
In this reading, you will learn about the various levels of cache for central processing units (CPUs) and how a CPU processes and executes instructions. Additionally, you will learn about overclocking CPUs to maximize processing speeds. IT Support professionals may use this information when purchasing, allocating, and/or configuring high-performance servers.
Cache
You may already be familiar with the term “cache”. In computer jargon, cache (pronounced “cash”) refers to a small amount of recently used data that is stored either on hardware or in software. The first time data is accessed, both the initial request for the data and the reply containing the data pass through multiple points on their journey. Depending on several variables, these points might include I/O devices, motherboard busses, RAM, cables, hard drives, applications, networks, the internet, cloud platforms, and more. If a computer needed to use these full paths every time it tried to access data, the entire transaction could take a relatively long time. Cache speeds up this process by holding a local copy of the most recently accessed data in temporary storage.
CPU cache
CPUs use a system of cache storage to help them quickly access data. A CPU cache is normally stored inside each core of the CPU. Older computers might store CPU cache in a transistor chip that is attached to the motherboard, along with a high-speed bus connecting the chip to the CPU.
CPU levels of cache
There are three levels of CPU cache memory:
Level 3 cache: L3 cache is the largest and slowest of CPU cache. However, it is often twice as fast as RAM. L3 is the first CPU cache location to store data after it is transferred from RAM. L3 cache is often shared by all of the cores in a single CPU.
Level 2 cache: L2 cache holds less data than L3 cache, but it has faster access speeds. L2 holds a copy of the most recently accessed data that is not currently in use by the CPU. Each CPU core normally has its own L2 cache.
Level 1 cache: L1 cache is the fastest and smallest of the three CPU cache levels. L1 holds the data currently in use by the CPU. Each CPU core usually has its own L1 cache.
Overclocking a cpu
Overclocking a CPU sets it to run at a higher CPU clock frequency rate than the manufacturer’s original specifications. For example, if a processor is labeled as having a 3.2 GHz base frequency rate, it may be possible to overclock the CPU to run at 3.5 GHz. Achieving a higher CPU clock frequency rate means the CPU can process a higher volume of instructions per nanosecond, resulting in faster performance. A computer user might want to overclock their CPU to improve sluggish speeds when performing processor-intensive tasks, like video editing or gaming.
Overclocking a CPU’s frequency involves three variables:
The base CPU clock frequency, often measured in GHz.
The core frequency, which is calculated by multiplying the base frequency by the CPU core multipliers.
The core voltage, which needs to be increased in small increments to meet the increasing power demand of the CPU during the overclocking process.
Warnings on overclocking
Overclocking the CPU can damage the computer if not configured properly. Operating a CPU at a higher speed can overheat the CPU and surrounding hardware, which can cause the computer system to fail. Additionally, overclocking the CPU can shorten the overall lifespan of the computer and void the computer’s warranty. It is better to avoid overclocking the CPU and instead purchase the appropriate CPU speed necessary to meet computing demands.
How to overclock a CPU safely
As an IT Support professional, you may be asked to overclock a CPU. There are steps you should follow to do this as safely as possible. Always make sure that the requestor understands the risks of overclocking before agreeing to perform this procedure.
Check if overclocking is supported: First, make sure the CPU is a model that is unlocked for overclocking. Not all CPUs can support overclocking, including most laptop CPUs. Check the CPU manufacturer’s documentation to determine if overclocking is possible for the CPU model. Both Intel and AMD provide overclocking guides and tools for supported CPU models (see below for links to these guides). Additionally, check the documentation for the computer’s motherboard model to ensure that it can support an overclocked CPU.
Clean the inside of the computer: Turn off and unplug the computer. While wearing an anti-static wristband, open the computer and use compressed air to remove any dust build-up that has accumulated. It is especially important to remove any dust from around the CPU, fans, and intake vents.
Ensure an appropriate CPU cooler is installed (critical): If the computer has a stock CPU cooler, it is most likely insufficient for cooling an overclocked CPU. Replace the stock CPU cooler with an advanced cooling system, like a liquid cooling system.
Follow the manufacturer’s instructions for overclocking the CPU: Using the detailed instructions from the manufacturer (see below for links to Intel and AMD’s guides):
Use benchmarking software to establish a baseline for the normal performance of the computer.
Set each CPU core multiplier to the value of the lowest multiplier using either the manufacturer’s overclocking software (recommended) or the BIOS. Then reboot the computer.
Increase each CPU core multiplier by 1 to increase the CPU frequency.
Test each increase for stability using the testing utility provided by the manufacturer.
Fix any problems flagged by the testing tools, especially temperature alerts. If the system becomes too unstable, roll back to the last frequency that produced a stable performance and stop overclocking the CPU.
If the voltage appears to become insufficient to support the new frequency, increase the voltage by 0.05V. Do not increase the voltage above 1.4V without specialized cooling hardware.
If the computer freezes or crashes, it has either become completely unstable or the CPU is not getting enough voltage to support the overclocked frequency. Use the BIOS to return to the last stable frequency or increase the voltage in 0.01V increments until stable.
If stable, reboot the computer before attempting the next increase.
Motherboard
Physical Storages - Hard Drives
Mobile Display Types
In this reading, you will learn about several types of displays used in modern mobile devices and monitors. As an IT Support professional, you may need to troubleshoot various types of displays. This might involve repairing damaged mobile device screens. You may even be responsible for selecting and ordering mobile devices for the employees of an organization. In your IT job role, you should have a basic understanding of the technology behind modern displays, as well as their common uses, positive features, and negative flaws. The top two technologies used in mobile system displays are Liquid Crystal Displays (LCD) and Light Emitting Diodes (LED).
Liquid Crystal Display (LCD)
LCDs use liquid crystal technology. Liquid crystals have the properties of both a liquid and a solid. The crystals can be aligned in a variety of patterns and manipulated with electricity. How the liquid crystals are arranged and manipulated inside display panels affects refresh rates, image quality, and display performance. LCDs require backlighting, often provided by LEDs. Displays that need backlighting are also called non-emissive or passive displays. The backlighting unit (BLU) requires extra space, which makes LCD panels thicker and less flexible than other displays. Polarizers on either side of the liquid crystal layer control the path of the backlight to ensure the light is aimed toward the user.
The following are common LCD display types used for mobile devices:
In-Plane Switching (IPS)
How it works: In IPS displays, the liquid crystals are aligned horizontally to the screen. Electricity is passed between the ends of the crystals to control their behavior.
Uses: IPS technology is used in touch screen displays and high-end monitors. They are often used for design, photography, video/film editing, animation, movies, and other media. They can also be used for games that rely on color accuracy and wide viewing angles, as opposed to speed.
Positives: IPS displays provide vibrant colors, high quality graphics, and wide viewing areas. Additionally, they offer excellent color reproduction, accuracy, and contrast.
Negatives: IPS displays are expensive. They have low refresh rates and slow response times. However, response times have been improving as the IPS technology evolves. IPS displays can be affected by “IPS Glow”, where the backlight is visible from side viewing angles.
Twisted Nematic (TN)
Twisted Nematic (TN) is the earliest LCD technology that is still in use today. The term nematic, which means “threadlike,” is used to describe the appearance of the molecules inside the liquid.
How it works: In TN displays, the liquid crystals are twisted. When voltage is applied, the crystals will untwist to change the angle of the light they transmit.
Uses: TN displays are appropriate for basic business use (e.g., email, document, and spreadsheet applications). They are also used for games that need rapid display response times.
Positives: TN displays are low cost, easy to produce, have excellent refresh rates, response times, and resolutions. They are versatile and can be manufactured for any size and/or shape.
Negatives: TN displays have narrow viewing angles, low image quality, color distortion, and poor color accuracy and contrast.
VA-Vertical Alignment
How it works: In VA displays, the liquid crystal molecules are vertically aligned. They tilt when electricity passes through them.
Uses: VA displays are intended for general purpose. Provides mid-range performance for graphic work, movies, and TV.
Positives: VA displays offergreat contrast, deep black shades, and fast response times. They are mid-range quality for refresh rates, image quality, viewing angle, and color reproduction.
Negatives: On VA displays, motion blur and ghosting occurs with fast-motion visuals.
Organic Light Emitting Diodes (OLED)
OLEDs are diodes that emit light using organic (carbon-based) materials when electricity is passed through the diodes. Displays that are able to convert electricity into light are called emissive or active displays.
How it works: The basic structure of an OLED display consists of an emissive layer placed between a cathode (which injects electrons) and an anode (which removes electrons). Electricity enters through the cathode layer, passes into the emissive layer and conductive layer to create light, then out through the anode layer.
Uses: OLED display technology can be used in foldable smartphones, rollable TVs, as backlighting in LCD TVs, for gaming, and inside VR headsets.
Positives: OLED displays deliver excellent picture quality, wide viewing angles, infinite contrast, fast response rate, and brilliant colors with true blacks. They are energy efficient, simpler to make, and much thinner than LCDs. OLED panels can be built to be flexible and even rollable.
Negatives: OLED displays are sensitive to light and moisture. Blue LEDs degrade faster than other LED colors causing color distortion over time. They are also prone to image retention and burn-in.
Active Matrix Organic Light Emitting Diode (AMOLED)
Active Matrix Organic Light Emitting Diode (AMOLED) and Super AMOLED are recent technologies used in smartphone displays.
How it works: AMOLED displays are a type of OLED panel that uses active matrix technology. Active-matrix displays have active capacitors arranged in a matrix with thin film transistors (TFTs). This technology enables the control of each individual pixel for rapid state changes, including changing brightness and color. AMOLEDs have touchscreen functions integrated into the screen.
Uses: AMOLED and Super AMOLED panels are used in high-end mobile devices, flat screen monitors, curved screens, and touchscreens.
Positives: AMOLED displays offer a high picture quality and fast response time. Color and brightness are consistent across the screen. Fast-moving images and motion are displayed clearly without blurring or ghosting. Super AMOLED panels can display a wider range of colors with enhanced contrast, which makes them easy to view in a wider variety of lighting conditions.
Negatives: AMOLED displays have the same problems as OLED displays (listed above) plus AMOLED panels can be difficult and expensive to manufacture.
Inorganic mini-LEDs (mLEDs)
Inorganic mini-LEDs (mLEDs) are a next-generation, emissive display technology.
How it works: Mini-LED displays work the same way that OLED displays work, but the individual LED size is much smaller at approximately 50-60 micrometers.
Uses: Mini-LED displays are used for LCD backlighting in smartphones, public information displays, signage, electronics, vehicle displays, and more. Mini-LEDs are also the tech behind “Liquid Retina XDR” screens.
Positives: Mini-LED displays offer ultra high luminance, superior HDR fineness, long lifetimes, thin panels, and are readable in sunlight. They are also less expensive than micro-LED displays.
Negatives: Mini-LED displays, when used as LCD backlighting, are limited by the properties of LCD technology. Mini-LED displays for mobile devices are more expensive than OLED displays.
Inorganic micro-LEDs (μLEDs)
Micro-LEDs (μLEDs) are also emissive, next-generation displays.
How it works: Micro-LED displays work the same way that OLED displays work, but the individual LED size is extremely small at 15 micrometers.
Uses: Micro-LED displays can be used in smartphones, AR/VR headsets, wearables, public information displays, wall-sized TVs, vehicle displays, and more.
Positives: Micro-LED displaysoffer superior performances across virtually all common display features, such as brightness, reaction speeds, power consumption, durability, color gamut, stability, viewing angles, HDR, contrast, refresh rates, transparency, seamless connectivity, and more. Micro-LED displays are readable in sunlight and have sensor integration capability.
Negatives: Micro-LED displays are expensive to manufacture and are not yet ready for mass production.
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