Chapter 6 Memory

© 2011 Pearson Addison-Wesley. All rights reserved.

Addison Wesley is an imprint of

Chapter 6Memory

Chapter 6Memory

The Complete A+ Guideto PC Repair 5/e


Click to add title in here

Click to add title in here

After completing this chapter you will be able to:• Differentiate between different memory

technologies• Plan for a memory installation or upgrade• Install and remove memory chips• Describe how memory works with the operating

system• Optimize memory for Windows-based platforms• Troubleshoot memory problems• Understand the benefits of teamwork

Chapter ObjectivesChapter Objectives


Memory OverviewMemory OverviewTypes of Memory:

• RAM (Random Access Memory) is volatile

memory found on the motherboard and stores

the operating system, the software

applications, and the data being used by

software.

• ROM (Read Only Memory) is a non-volatile

type of memory that keeps data in chips even

when the computer is shut off.

Types of RAM:

• DRAM (Dynamic RAM) is cheaper than

SRAM, but slower. It requires periodic

refreshing of the electrical charges holding the

1s and 0s.

• SRAM (Static RAM) is faster, but more

expensive than DRAM. It is also known as

cache memory or L2 cache.


• The CPU should never have to wait to receive an instruction

• Using pipelined burst cache speeds up processing for software applications.

Tech TipsTech Tips


• Refreshing – Rewriting the information inside memory chips.

• Nanosecond – A billionth of a second.• Pipeline – Separate internal data buses that

operate simultaneously inside the processor.• Cache Memory – Designed to increase processor

efficiency. − Can be found on the motherboard, but normally is found inside

the CPU or CPU housing. − Cache memory holds the most frequently used data so the CPU

does not return to the slower motherboard DRAM chips to obtain the data.

Memory TermsMemory Terms


Memory Physical PackagingMemory Physical Packaging

• DIP (Dual In-line Package) – A chip

that has a row of legs running down

each side.

• SIMM (Single In-line Memory

Module) – Available in 30-pin and

72-pin configurations.

• DIMM (Dual In-line Memory

Module) – 168-pin, 184-pin and 240-

pin configurations.


Memory Physical PackagingMemory Physical Packaging


Planning the Memory InstallationPlanning the Memory Installation

Key points for planning a memory installation

- Refer to the system or motherboard documentation to see what type of memory is supported

- Determine what features are supported

- Determine how much memory is needed

- Determine how many of each memory module is needed

- Research prices and purchase memory module(s)


Tech TipsTech Tips

• Use the type of memory chips recommended by the motherboard manufacturer.

• It is best to use the manufacturer-specified type of memory chips. – The chipset and motherboard design are very

specific as to what type, and features the memory chips can have.


Memory TechnologiesMemory Technologies

• Technology has provided faster DRAM speeds without increasing the cost too greatly.


Memory Technologies (cont.)Memory Technologies (cont.)


Types of DIMMsTypes of DIMMs


Memory FeaturesMemory Features

• Parity – A method for checking the accuracy of data in or out of the memory chips• Non-parity – Memory chips that do not use

any error checking

• ECC (Error Correcting Code) – An alternative to parity checking that uses a mathematical algorithm to verify data accuracy


Memory LimitationsMemory Limitations

• Specific operating systems have a memory limitation.• 32-bit Windows has a 4GB memory limitation.

– Do not install over 4GB on a computer with a 32-bit operating system such as XP, Vista, or 7.

– Even with 4GB, the 32-bit operating system shows less than 4GB because some of that memory space is used for things attached to the PCI bus.

• The motherboard has a memory maximum


Amount of Memory to InstallAmount of Memory to Install

• Memory is one of the easiest upgrades to do to a computer to improve performance.

• Amount of memory needed depends on– Maximum allowed by the operating system– Types of applications used– How many applications the user wishes to

have open at the same time– Type of computer– Maximum allowed by motherboard


Minimum Memory RecommendationsMinimum Memory Recommendations


Planning the Memory Installation Planning the Memory Installation

Common Memory Capacities:

• DIMM Modules− 256MB, 512MB, 1GB, 2GB, 4GB, 8GB

(Note: and more before this book is revised.)

• RIMM Modules− 64MB, 128 MB, 256MB, 512MB


Planning the Memory Installation Planning the Memory Installation

The Amount of Memory to Install


Planning for MemoryPlanning for Memory

• Single-sided memory - A memory module that the CPU accesses at one time. • The module has one “bank” of memory and 64 bits

are transferred out of the memory module to the CPU.

• More appropriately called single-banked memory. • Note: that the memory module may or may not have

all of its “chips” on one side



• Double-sided memory - A single memory module that contains two memory modules in one container. − Data is still sent to the CPU 64 bits at a time. − Some use the terms single-sided and double-sided to

describe memory modules that have chips on one side (single-sided) or both sides (double-sided).

− Another name is double-ranked memory.



Dual-channel - The motherboard memory controller chip handles processing of memory request more efficiently by handling two memory paths simultaneously.


Tech TipTech Tip

• Dual-channel should use exact memory module pairs.– Channel A and Channel B (sometimes labeled

Channel 0 and Channel 1) should have matching memory modules.

– Buy a kit to ensure that the two modules are exact.


Dual-Channel ExamplesDual-Channel Examples


Dual-Channel ExampleDual-Channel Example



• The researching and buying step of planning for your memory installation/upgrade is most likely the step that can make your head spin. − Different Web sites list memory differently. − Some give you too much information, some too little.



• A confusing aspect of buying memory is memory speed. − Memory speed can be represented as ns

(nanoseconds), MHz, or the DDR PC rating.

• Access Time - The amount of time it takes to retrieve data from memory or a device.

• CL rating (CAS latency rating)- The amount of time in clock cycled that passes before the CPU moves on to the next memory address.• A CL2 rating is faster than a CL4 rating.


Nanoseconds and the Race TrackNanoseconds and the Race Track• The lower the number of nanoseconds,

the faster the access time of the memory chips. – Think of access time like a track race - the

person with the lowest time wins the race and is considered to be the fastest.

– Chips with lower access times (lower amount of nanoseconds) are faster than those with higher access times (larger numbers).


Laptop MemoryLaptop Memory

• SO-DIMM (small outline-DIMM)- Special, smaller DIMM used in laptop computers.

• microDIMM- A type of DIMM used in portable computers such as a laptop.

• SO-RIMM (small outline-RIMM)- Special, smaller RIMM used in laptop computers.


Installing Memory OverviewInstalling Memory Overview

• Determine which chip capacities can be used for the system. Look in the documentation included with the motherboard or the computer for this information.

• Determine how much memory is needed.• Determine what capacity chips go in each bank by

drawing a diagram of the system, planning the memory population on paper, and referring to the documentation of the system or motherboard.


Memory Safety ReminderMemory Safety Reminder

• Before installing a memory module, power off the computer, disconnect the power cord from the back of the computer, and use proper antistatic procedures. – Memory modules are most susceptible to ESD. If

ESD damages a memory module, a problem may not appear immediately and could be intermittent and hard to diagnose.


Removing a DIMM/RIMMRemoving a DIMM/RIMM

• When removing a DIMM or a RIMM and using proper ESD prevention techniques, push down on the DIMM retaining tabs that clasp over the DIMM.- Be careful not to overextend the tabs when pushing

on them.- If a plastic tab breaks, replace the motherboard.

• The DIMM/RIMM lifts slightly out of the socket. • Ensuring you are grounded to prevent, ESD, lift

the module out of the socket once it is released.


Removing a DIMM/RIMMRemoving a DIMM/RIMM

• To remove a DIMM or a RIMM, push down on the outside edges of the DIMM’s retaining tabs. The DIMM/RIMM lifts slightly out of the socket.


Installing a DIMM/RIMMInstalling a DIMM/RIMM

• A DIMM/RIMM has one or more notches on the bottom.− The DIMM inserts into the memory socket

only one way.− The DIMM memory socket has two tabs that

align with the DIMM notches.− The DIMM will not insert into the memory

socket unless it is oriented properly.


Installing a DIMM/RIMMInstalling a DIMM/RIMM

• To install a DIMM/RIMM, align the notches with the socket and press down until the tabs close.

• DIMM/RIMM is inserted straight down into a socket.

• If the DIMM/RIMM does not insert easily, check the notch for proper alignment.


Windows Disk CachingWindows Disk Caching

• Virtual Memory - A method of simulating extra memory by using the hard disk space as if it were RAM.

• Swap file - A temporary file in hard disk space used by Windows that varies in size depending on the amount of RAM installed, available hard drive space, and the amount of memory needed to run the application.


Windows Disk CachingWindows Disk Caching

• Pages – In Windows disk caching, memory space is divided into 4KB blocks called pages.• The operating system swaps or pages the application to

and from the temporary swap file on the hard drive as needed if the amount of RAM is not large enough to handle the application.

• PAE (physical address extension) - A feature provided by Intel that allows up to 64GB of physical memory to be used for motherboards that support it.


Hard Drive Swap File TipHard Drive Swap File Tip

• If multiple hard drives are available, a technician might want to move the swap file to a different drive. – Always put the swap file on the fastest hard drive

unless that hard drive lacks space. – It is best to keep the swap files on a hard drive that

does not contain the operating system. – You can configure the computer to place the swap file

on multiple hard dives.


Monitoring Memory Usage Under WindowsMonitoring Memory Usage Under Windows

• Performance utility - Windows utility accessed through Task Manager that monitors memory and other hardware parameters usage aspects.


Old Applications Under Windows Old Applications Under Windows

- NTVDM (NT Virtual DOS Machine)- Simulates a DOS environment inside NT Workstation and higher when an 8- or 16-bit application is being run.

- Many dated applications do not operate in the NT/2000/XP environment because these applications frequently make direct calls to hardware, which NT, 2000, XP, Vista, and 7 do not allow.


Troubleshooting Memory ProblemsTroubleshooting Memory Problems

• The following tips help with memory management - Add more RAM- Check installation - Empty Recycle Bin- Adjust virtual memory size- Change the virtual memory settings- Do not put the swap file on multiple partitions that reside on the

same hard drive. - Put the swap file on a hard disk partition that does not contain

the operating systems.- Put the swap file on the fastest hard drive.- Remove the desktop wallpaper scheme or use a plain one.- Adjust your Temporary Internet Files setting- Defragment the hard drive.


Flash MemoryFlash Memory

• Flash memory- A type of non-volatile memory that holds data when the power is off.

• CompactFlash (CF) - A type of removable flash memory storage that can be inserted into many devices such as disk drives, cameras, PDAs, and tablet PCs.

• SmartMedia - A card, smaller than a credit card, used to hold audio and video files.

• USB flash drives - Sometimes called a flash drive or a memory stick, USB flash drives allow storage via a USB port,


Tech TipTech Tip

• No.1 cause of Flash Drive failure is improper removal– When finished using the Flash drive, double-click the

Remove Hardware icon located in the System Tray. – The icon has a green arrow. – You may have to click on the left arrow or up arrow to

see this icon. – Click Safely Remove Hardware. – Select the appropriate Flash drive, then click Stop and

OK. – When a message appears that you can safely remove

the drive, pull the Flash drive from the USB port.


Soft Skills - TeamworkSoft Skills - Teamwork

- Much of a technician’s work is completed alone.

- Technician’s have one or more peers, a supervisor, and a network of partners such as suppliers, subcontractors, and part-time help.

- Do not lose sight of the business-first mentality- remember technicians play a support role.- As a technician, you are an EXPENSE on the

spreadsheet.

- Technicians should be good team players and have good sportsmanship.


Addison Wesley is an imprint of

Questions???Questions???

Documents

Chapter 6 Memory