cases and power supplies - mesa, arizona

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Personal Computer Systems

Cases and Power Supplies Cases influences the motherboard form factor choice

must support all internal devices

must allow for good air flow

available in different sizes

Power Supplies• provide power to all computer components so

must be chosen based on current and future needs

convert AC power from the wall socket into DC, which is a lower voltage

deliver different voltage levels to meet different internal component needs

Cables, connectors, and components are designed to fit together snugly--never force any connector or component.

Connectors are generally “keyed,” which means they fit in only one way.

Some power supplies are proprietary to be used with proprietary connectors required by some motherboards.

Power Supplies

On the back of the power supply is a small switch called the voltage selector switch.

This switch sets the input voltage to the power supply to either 110V/115V or 220V/230V. The correct voltage setting is determined by the country where the power supply will be used.

Setting the voltage switch to the incorrect input voltage could damage the power supply and other parts of your computer. If a power supply does not have the voltage selector switch, your power supply will automatically detect and set the correct voltage.

If you suspect the power supply is not functioning, you can test it with a power supply tester.

A computer can tolerate slight fluctuations in power, but a significant deviation can cause the power supply to fail. An uninterruptible power supply (UPS) can protect a computer from problems caused by changes in power. A UPS provides power for a computer using a power inverter. A power inverter provides AC power to the computer from a built-in battery by converting the DC current of the UPS battery into AC power.


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Power Supply Consumption

Below are some common computer components and their average power consumption:

Motherboard 35W (low end) 75W (high end)

CPU 77W (low end) 120W (top end)

Memory 3W (low end) 4.5W (high end) *

Video Card(s) 70W(low end) 470W(top end)**

SSD Drive 1.5W

3.5 HDD Drive 7.5W

SATA Blu-ray Drive (25-30GB) 30W

SATA DVD Drive (4.7 to 9.4GB) 20W

80 mm Case Fan (2,000 RPM) 1.5W

(*) DDR3 memory operates with lower voltages; lower voltages lead to lower power consumption.

(**) under heavy operation.

A few devices still not accounted for are: USB drives without power supply, adapter cards, extra fans, etc.


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Ohm’s Law

There is a basic equation that expresses how three of the terms relate to each other. It states voltage is equal to the current multiplied by the resistance. This is known as Ohm's Law.

• V = IR

In an electrical system, power (P) is equal to the voltage multiplied by the current.

• P = VI

If wire from the power supply is carrying 120W of power and 24A of current, which color(s) of cable is the wire?

• V = P/I

Motherboard Form Factors

The form factor of motherboards pertains to the size and shape of the board.

It also describes the physical layout of the different components and devices on the motherboard.

Various form factors exist for motherboards.


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Motherboards

the main printed circuit board

contains the buses or electrical pathways found in a computer—buses allow data to travel among the various components

also known as the system board, the backplane, or the main board

accommodates CPU, RAM, expansion slots, heat sink/fan assembly, BIOS chip, chipset, sockets, internal and external connectors, various ports, and the embedded wires that interconnect the motherboard components

The amount of memory that can be installed and type of connectors that will be on the motherboard are determined by the chipset.

• The Northbridge (generally closest to the CPU) controls access to the RAM, video card, and the speeds at which the CPU can communicate with them. The video card is sometimes integrated into the Northbridge.

• The Southbridge, in most cases, allows the CPU to communicate with the hard drives, sound card, USB ports, and other I/O ports.


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Motherboards


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Q: Which chip controls access to the RAM, video card, and the speeds at which the CPU can communicate with them?

A: Northbridge

Q: What factors that must be considered when choosing a computer case?

A: internal drive locations, the size of the motherboard, the size of the power supply

Q: Where can the input voltage selection be changed from 110 volts to 220 volts on a computer system?

A: on the back of the power supply

Let’s see what you have learned . . .

Log onto NetAcad and Review MaterialCases , Power Supply , & Motherboard

Then preview Quiz 1

Read through Chapter 1 looking for Key terms from Quiz 1

Remember to Review All material (ex. Figures, video, notes)

When you feel ready for Quiz 1…

Attempt it as an “Open Book” Quiz

Part of Video 1 : Adding to Motherboard


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Q: Which chip controls access to the RAM, video card, and the speeds at which the CPU can communicate with them?

A: Northbridge

Q: What factors that must be considered when choosing a computer case?

A: internal drive locations, the size of the motherboard, the size of the power supply

Q: Where can the input voltage selection be changed from 110 volts to 220 volts on a computer system?

A: on the back of the power supply

From your Cornell Notes : Let’s see what you have learned . . .


Internal PC Components Motherboards

• backbone of the computer

• interconnects computer components

CPU (PGA, LGA)• the brain of the computer

• most processing is done by the CPU

Cooling Systems• dissipates the heat generated by computer components

Memory (ROM and RAM)• RAM: Stores data temporarily, aiding processing

• ROM: Stores data permanently; often storing firmware and low level programs


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Central Processing Unit (con’t.)

Some CPUs incorporate hyperthreading or hypertransport (AMD architecture) to enhance the performance of the CPU.

The amount of data that a CPU can process at one time depends on the size of the processor data bus (FSB).

The front side bus (FSB) or system bus is the physical bi-directional data bus that carries all electronic signal information between the central processing unit (CPU) and the Northbridge. Some computers also have a back side bus which connects the CPU to a memory cache.

Speed of the CPU is measured in cycles per second-megahertz (MHz) or gigahertz (GHz).

Overclocking is a technique used to make a processor work at a faster speed than its original specification.

The opposite of overclocking is CPU throttling. CPU throttling is a technique used when the processor runs at less than the rated speed to conserve power or produce less heat. Throttling is commonly used on laptops and other mobile devices.

Central Processing Unit (CPU) Two major CPU architectures related to instruction sets:

• Reduced Instruction Set Computer (RISC)

• uses a small, highly optimized set of instructions, rather than a more specialized set of instructions

• Complex Instruction Set Computer (CISC)

• uses a broad set of instructions, resulting in fewer steps per operation


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Central Processing Unit (con’t)

The latest processor technology has resulted in CPU manufacturers finding ways to incorporate more than one CPU core onto a single chip.

Dual Core CPU - two cores inside a single CPU

Triple Core CPU - three cores inside a single CPU

Quad Core CPU - four cores inside a single CPU

Hexa-Core CPU - six cores inside a single CPU

Octa-Core CPU - eight cores inside a single CPU

ROM and RAM Programmable Read-only memory (PROM)

Basic instructions for booting the computer and loading the operating system are stored in ROM.

ROM chips retain their contents even when the computer is powered down.

Information is written to an EEPROM chip after it is manufactured. EEPROM chips are also called Flash ROMs. An EEPROM chip can be erased and re-written without having to remove the chip from the computer. EPROM chips can be erased by exposure to UV light.

Random-access memory (RAM)

RAM is temporary storage for data and programs that are being accessed by the CPU.

RAM is volatile memory, which means that the contents are erased when the computer is powered off.

More RAM means more capacity to hold and process large programs and files, as well as enhance system performance.


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Memory Modules

Memory modules are memory chips that have been soldered on to a special circuit board for easy installation and removal.

Dual Inline Memory Module (DIMM) is a circuit board that holds SDRAM, DDR SDRAM, and DDR2 SDRAM chips.

RAM Bus Inline Memory Module (RIMM) is a circuit board that holds RDRAM chips.

Small Outline DIMM (SODIMM) is a smaller, more condensed version of DIMM which provides random access data storage that is ideal for use in laptops, printers, and other devices where conserving space is desirable.

The speed of memory has a direct impact on how much data a processor can process because faster memory improves the performance of the processor. As processor speed increases, memory speed must also increase.


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Cache and Error Checking

Cache• SRAM is used primarily as cache memory to store the most

frequently used data.

• SRAM provides the processor with faster access to the data than retrieving it from the slower DRAM or main memory.

Error Checking• Memory errors occur when the data is not stored correctly in the

RAM chips.

• The computer uses different methods to detect and correct data errors in memory:

• nonparity (no error-checking bit)

• parity (extra error-checking bit)

• ECC most often used in server environments


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Q: Which component controls the communications and interactions between the CPU and other components on the motherboard?

A: chipset

Q: Which type of memory is primarily used as cache memory?

A: SRAM

Q: What type of chip can be erased and re-written without having to remove the chip from the computer?

A: EEPROM

Q: What is this process called?

A: flashing



Internal PC Components (cont.) Adapter Cards and Expansion Slots

• adapter cards extend computer functionality

• adapter cards connect to the motherboard through expansion slots

Storage Devices• designed to permanently store user data,

user applications and the operating system (PATA,SATA, Hybrid or SSD)

• Solid state drives (SSDs) do not have moving parts, which results in faster access to data, higher reliability, reduced power usage.

• can be internal or external to the computer

• generally measured in RPM (revolutions per minute)

Video Ports• connects a video system to an external display device such as a monitor or projector

• Video systems are often designed as an adapter card.

General Ports• provide connectivity between the motherboard and various external devices such as printers,

external storage and video cameras


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Thunderbolt is an interconnect technology developed by Intel in cooperation with Apple.

Thunderbolt combines PCI Express and DisplayPort into a single connection, allowing for a combination of up to six peripherals, like storage devices and monitors, to be daisy-chained together.


Internal PC Components (cont.)


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RAID Levels RAID provides a way to store data across

multiple hard disks for redundancy.

RAID Level

Min # of Drives

Description

0 2 Data striping without redundancy (i/o improvement)

1 2 Disk mirroring (high performance with data protection)

2 2 Error-Correcting Coding

3 3 Byte-level data striping with dedicated parity

4 3 Block-level data striping with dedicated parity

5 3 Block-level data striping with distributed parity

6 4 Independent Data Disks with Double Parity

0/1 4 Combination of data striping and mirroring

10 4 Mirrored set in a striped set

Raid 0 and 1 Raid 5 and 10

Adapter Slots

• PCI—shared bandwidth, which is slower• PCI-x—uses a 32-bit bus and is 4 times fast than PCI• PCI-e—point-to-point, serial connection, which allows slots to be

linked together for a faster connection

Size Matters


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Ports

• PCI – 133 Mbps, 32 bits, 33 MHz

• AGP – 266 Mbps, 32 bits wide, 66 MHz

• PCI-e – x1 equates to 1 lane of data transfer

• x16 equates to 16 lanes of data transfer


External Ports and Cables Video Ports and Related Cables

• A few different standards govern video traffic between the computer and external video devices.

• HDMI and DisplayPort are examples of video ports that require a specific cable to operate and are usually connected to high-definition TVs or computers with audiovideo devices.

Other Ports and Related Cables• Motherboards have a number of other ports used for device

connectivity; USB is a common example.

Adapters and Converters• Adapters and converters can be a solution if a motherboard does not have the proper

port to connect to a device.

• Adapters do not usually process the signal; they simply redirect it to another pin.

• Converters are more likely to process and transform the signal, converting it to be accepted by an existing port.


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Select Computer Components

Select PC Components Select the Motherboard, CPU, Case and Memory

• CPU, memory, motherboard and case choices are interrelated.

• The motherboard should support all customer required applications and still fit properly in the case.

• The case should host the motherboard, the proper power supply and provide good airflow for the internal components.

• The CPU must be compatible with motherboard CPU slot and voltage; it should be compatible with the chosen memory speed for maximum performance.

• The memory must also be compatible with motherboard memory slots and voltage. The speed of the RAM must be supported by the chipset.

• The amount of memory will depend on the type of applications requested by the customer.


Select PC Components (cont.) Select the Case and Fans

• Case and fans must be chosen to maximize internal airflow.

• The fans must fit the case and be within the power limits provided by the power supply.

Select the Power Supply• The power supply should be selected based on the maximum amount of

power required by all the internal components.

• Remember that some components will draw more power while under heavy load.

Select Adapter Cards• Make sure the motherboard has compatible expansion slots to

support the adapter cards.

• The motherboard must also have enough expansion slots to receive all the required adapter cards.

• Customer needs will define what adapter cards must be procured and installed.


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Select PC Components (cont.) Select Hard Drives

• Important hard drive factors to be considered are speed, storage space and communication interface type.

• The drive’s underlying technology (HDD vs Hybrid vs SSD) directly impacts speed.

Select a Media Reader• The media reader must be compatible with customer

media.

Select Optical Drives• Make sure the drive is compatible with customer media.

• Other factors to consider are speed, communication interface type and the ability to write to the media.

Hard Drive Connectors PATA (Parallel ATA) hard drives:

• originally called ATA (Advanced Technology Attachment)

• with the introduction of SATA, ATA was renamed to PATA

• can use a 40-pin / 80-conductor cable or a 40-pin / 40-conductor cable

SATA (Serial ATA) hard drives:

• connect to the motherboard using a serial interface

• have a higher data-transfer rate than PATA drives

• smaller data cable allows for improved airflow

• eSATA (external SATA)

SCSI (Small Computer Systems Interface) hard drives:

• use a 50-pin, 68-pin, or 80-pin connector

• Up to 15 SCSI drives can be connected to a SCSI drive controller.


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Select PC Components (cont.)

Select External Storage• Important factors when selecting external storage are

storage space, speed and communication interface.

• Make sure the computer has enough ports to accommodate the external devices and peripherals.

• Note: Some external devices do not require an external power supply but rely on a second USB port for power.

Select I/O Devices• The selection of I/O devices is application specific and

will depend on customer requirements.

• Make sure the computer has enough communication ports and that they are compatible with the types required by the I/O devices.

Ports and Cables Serial ports transmit one bit of data at a time.

A telephone cable (RJ11) is used to connect a modem to a telephone outlet.

USB is a standard interface for connecting hot-swappable peripheral devices to a computer. Some devices can also be powered through the USB port. A single USB port in a computer can support up to 127 separate devices with the use of multiple USB hubs.

• USB 1.0 (12 Mbps), 2 (480 Mbps), 3 (4.8 Gbps)

FireWire is a high-speed, hot-swappable interface that can support up to 63 devices. Some devices can also be powered through the FireWire port. • The IEEE 1394a standard supports data rates up to 400

Mbps and cable lengths up to 15 feet (4.5 m). This standard uses a 6-pin connector or a 4-pin connector.

• The IEEE 1394b standard supports data rates in excess of 800 Mbps and uses a 9-pin connector.

A parallel cable (IEEE1294) is used to connect parallel devices, such as a printer or scanner, and can transmit 8 bits of data at one time.


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Input Devices

Input devices are used to enter data or instructions into a computer: • mouse and keyboard

• KVM switch

• gamepad and joystick

• digital camera and digital video camera

• biometric authentication device

• touch screen

• scanner

Output Devices

Monitors and Projectors:• Liquid crystal display (LCD) is commonly

used in laptops and some projectors. LCD comes in two forms, active matrix and passive matrix.

• A light-emitting diode (LED) display is an LCD display that uses LED backlighting to light the display.

• An Organic LED (OLED) display uses a layer of organic material that responds to electrical stimulus to emit light.


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Output Devices (Terms)

Pixel - The term pixel is an abbreviation for picture element. Pixels are the tiny dots that comprise a screen. Each pixel consists of red, green, and blue (RGB).

Dot pitch - Dot pitch is the distance between pixels on the screen. A lower dot pitch number produces a better image.

Contrast ratio - The contrast ratio is a measurement of the difference in intensity of light between the brightest point (white) and the darkest point (black). A 10,000:1 contrast ratio shows dimmer whites and lighter blacks than a monitor with a contrast ratio of 1,000,000:1.

Refresh rate - The refresh rate is expressed in Hertz (Hz) and refers to how often per second the image is rebuilt. A higher refresh rate produces a better image.

Aspect ratio - Aspect ratio is the horizontal to vertical measurement of the viewing area of a monitor. For example, QSXGA measures 2,560 pixels horizontally by 2048 pixels vertically which creates an aspect ratio of 5:4. If a viewing area was 16 inches wide by 12 inches high, then the aspect ratio would be 4:3. A viewing area that is 24 inches wide by 18 inches high also has an aspect ratio of 4:3.

Native resolution - Native resolution is the number of pixels that a monitor has. A monitor with a resolution of 1280x1024 has 1280 horizontal pixels and 1024 vertical pixels. Native mode is when the image sent to the monitor matches the native resolution of the monitor.

Configurations for Specialized Computer Systems

Specialized Computer Systems Thick and Thin Clients

• Thin clients have little processing power and are designed to act as a terminal to a server (thick client).

• Thick clients have more powerful CPUs, more memory and their own storage. They serve as processing stations for thin clients.

CAx Workstations• designed to support CAD and CAM applications

• plenty of RAM, fast disks, powerful CPU and special

input devices are common resources.

Audio and Video Editing Workstations• common editing workstation resources include

much RAM, fast disks, powerful CPU and special adapter cards such as audio and video capture.


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Configurations for Specialized Computer Systems

Specialized Computer Systems (cont.) Virtualization Workstations

• These workstations are designed to run virtual computers

• Virtual computers use and share the workstation’s physical resources such as CPU, memory and disks.

• The selection of physical resources will depend on the number and purpose of the virtual machines. Powerful CPU and sufficient RAM are suggested.

Gaming PCs• Due to high resource requirements of modern games, gaming PCs are very resource

demanding.

• A few requirements of gaming PCs are: top end CPU, lots of fast RAM, fast disks, high performance input devices and audio systems.

Home Theatre PCs• These computers must be able to play various media formats

and, in some cases, receive TV signals.

• Common HTPC requirements include powerful CPU, fast RAM, large disks, fast NIC and video card with TV input.

Q: Name a storage device that uses magnetic medium for storing data.

A: hard drive

Q: Which two pieces of information are needed before selecting a power supply?

A: the form factor of the case and the total wattage of all the components

Q: Which RAID level has the highest performance without redundancy?

A: RAID 0



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This chapter introduced the components that comprise a personal computer system and what to consider when choosing upgrade components.

Information technology encompasses the use of computers, network hardware, and software to process, store, transmit, and retrieve information.

A personal computer system consists of hardware components and software applications.

The computer case and power supply must be chosen carefully to support the hardware inside the case and allow for the addition of components.

The internal components of a computer are selected for specific features and functions. All internal components must be compatible with the motherboard.

Use the correct type of ports and cables when connecting devices.

Typical input devices include the keyboard, mouse, touch screen, and digital cameras.

Typical output devices include monitors, printers, and speakers.

Cases, power supplies, the CPU and cooling system, RAM, hard drives, and adapter cards, must be upgraded when devices fail or no longer meet customer needs.

Specialized computers require hardware specific to operate. The type of hardware used in specialized computers is determined by how a customer works and what a customer wants to accomplish.

Chapter Summary

Summary

cases and power supplies - mesa, arizona

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