Memory

Josh Johnson - Luke Schriver - Ryan Jones

Memory Introduction 2 Types of RAM

RAM (Random Access Ram)DRAM (Dynamic)

A series of DRAM chips on a “RAM stick”

Billions of capacitors and transistors can fit on a single memory chip

Transistors act as a gate for electronic signals coming into the memory cell

DRAM chips are made up of memory cells each assigned a hex address

Cells are assigned addresses by the IMC

IMC (integrated memory controller

Manages flow of data going to and from the RAM

Address Bus connects the IMC to CPU

DRAM(cont)SDRAM(synchronous DRAM)

is a generic name for various kinds of dynamic random access memory (DRAM) that are synchronized with the clock speed that the microprocessor is optimized for. This increases the number of instructions that the processor can perform in a given time.

DDR RAM

Double Data Rate RAM is a subset of SDRAM

Introduced in 1996, newest generation is DDR4

DDR utilizes both the rising and falling edge of the system clock, potentially doubling the speed of the memory.

Subsets of RAM

Single-in-line Memory Module Usually holds 9 chips, the 9th being an error checking chip

Mostly Used in 80’s to 90’s, has been since replaced by DIMMs

The connector pins on SIMM RAM are redundant on the back side of the module

Dual-in-line Memory ModuleHave separate electrical contacts on both sides of the module

Have 64-bit paths (SIMMs only had 32 bit)

SODIMM(small-outlineDIMM)

Used in compact systems such as notebooks

SRAM (Static)Used for the cache in the CPU, LCD screens and printers

Composed of 6 transistors, 1 capacitor and switch buffer.

When the buffer is on or off it represents 1 bit of data, either a 1 or 0

Does not need to be refreshed as DRAM does. This makes it more quick but also more expensive than DRAM.

Nonvolatile- When power is lost, the data in the RAM will remain intact

http://youtube.com/v/GtEbrY4nDIQ

Memory Installation When installing RAM it is important to consult the motherboard

documentation to be sure you are installing the correct kind.

When deciding on a RAM these are a few factors one should consider:Packaging - the packaging controls both the physical size of the memory module and

the memory standard, and if you purchase the wrong type of RAM, it will probably not fit.

Capacity (size) - refers to the storage capacity of the memory module (i.e. 256 MB, 512 MB, 1GB)

Frequency (speed) - you should match the memory frequency with the frequency supported by the system bus/memory controller.

CAS Latency - a delay between the time the data is requested and the time that the data is available on the module’s output pins. So for memory modules of the same type and frequency, a lower CAS number indicates less delay, which leads to a “faster” RAM.

There are many websites where you can look up your system to find the correct memory to install.

Memory InstallationDuring the memory installation process remember the following:

Be sure to take the proper steps to prevent ESD, as memory modules are very sensitive.

Install memory in the correct slot since some system boards require that you use specific slots.

Align the memory before inserting and do not force the module into place.

Most RAM is held in place with small tabs. To remove RAM, push down the tabs to rotate them back, then pull RAM straight up.

For a dual-, triple-, and quad-channel configuration, modules must be installed in matching sets (capacity and speed), preferably of the same manufacturer and model.

After you install the memory, power on the system and check for any errors.

Most systems will configure memory settings automatically based on information from the EEPROM chip.

Memory Installation (video)

Memory TroubleshootingMemory is an electronic component so it usually doesn’t degrade like

a mechanical component

Common ways memory can get damagedESD

Improper handling

Power spike

Symptoms of Memory ErrorsTroubleshooting memory is difficult because the errors are

intermittent

Common symptomsSystem lockup

Blank screen

OS won’t turn on all the way

Blue screen error

Identifying Memory ErrorsCan be caused by hardware issues and also by software

Example: Poorly written application attempts to use an address in RAM that has already been

given to another process. OS then halts entire system to prevent data corruption then blue screen is displayed.

Above error only happens when OS attempts to write to memory so until then the computer will operate normally, then blue screen.

What is a Blue Screen Error?Blue screens provide useful information that could be used to

diagnose the issue (Windows 7 and earlier)

Troubleshooting using the Blue screenMake note of the memory address given with error

If that address changes each time, then it is likely a poorly written application

If address remains the same then memory module may be going bad

In Windows 8 only minimal information is displayed by a blue screen error so debugging may be difficult

Testing Memory Modules ManuallyIf you suspect a memory module is bad, then you have to test the

system to see which one

Option 1: Remove memory modules from system, one at a time, until error goes away

Option 2:Use a software memory tester. During this test it will check all memory locations on

the memory module and report whether the module is good or bad

Memory Installation IssuesESD protection

Take proper static prevention measures when working with memory modules

Use an anti-static bag to transport memory modules

When handling be sure to use a static mat to ground yourself

Improper SeatingNeed to push hard on the module when installing, but not too hard

Modules will have tabs that will be up or down when properly seated

Memory CompatibilityDDR memory has a built in clock, need to make sure that matches clock of the BUS

on the motherboard

Testing MemoryMemTest86

Software memory testing utility

Downloadable via memtest86’s website in free or paid form

In order to use we need to download file then burn to a disc

Upon OS load the memtest86 disc will begin testing memory and display on the right side of your computer how many CPUs are found and how many were actually started

Every time an error is discovered with the memory module an error will be displayed on the bottom of your screen in red

Takes about 20 - 30 minutes for a complete scan pending on how much memory currently used

Memory Troubleshooting Facts (From testout)(Error) The system boot fails and sounds a beep code

No memory is installed or the memory was not detected

The system boots, but the display remains blankVideo card or memory module is not seated correctly, or using unsupported memory

System boots, but memory count is incorrectPOST failed to recognize all of memory. Happens with incompatible memory

installation

Common Error Messages Memory mismatch error

Memory parity interrupt at x

Memory address error at x

Memory failure at x, read y, expecting z

Memory verify error at x

Common Software Errors With MemoryRegistry error

Parts of the registry are written to faulty sections of RAM

Exception ErrorCauses program to abort and return the user to the OS

General protection error (GPF)When processors detect a protection violation, it will stop executing the code and

send a GPF interrupt

Page faultWhen a running program attempts to access a memory page that is not currently

mapped by memory

Critical Times a Memory Error May OccurFirst boot of a new computer

Memory is not seated correctly or motherboard is defective

After a memory upgradeEnsure that memory is compatible, was installed, and configured correctly

After software installationNew software requires more memory and can cause problems

After hardware installation or removalIncompletely or improperly installed hardware can cause errors

Questions

RAM QuestionsWhich of the following most likely contains SODIMM memory?

a)Printers

b)Notebooks

c)Servers

d)Desktop Systems

Which of the following are used to identify Memory Modules

a)AGP

b)PATA

c)SATA

d)DIMM

A customer needs to use several applications. Currently the computer cannot keep all the necessary applications open at the same time. Which of the following components should you consider upgrading?

a)System Board(motherboard)

b)CPU

c)Hard Disk Drive (HDD)

d)Memory

Which of the following is the most common method for removing RAM from a motherboard?

A.Pull the RAM module up from one corner, then twist to release the other corner.

B.Remove the screw from the one side; pull straight up to remove the RAM.

C.Tip the RAM module at a 45 degree angle while pulling.

D.Move the tabs holding the RAM out of the way; pull straight up to remove the RAM.

Installation Questions

With a memory module read request, there is a delay between the time of the data request and the time the data is available for output from the memory module.

What is this delay called?

A.Frequency

B.CAS Latency

C.Capacity

D.Clock cycle parity

You are in a carpeted office lighted by fluorescent bulbs. You are preparing to add memory modules to a user's computer. The user has already unpacked the memory modules and stacked them on top of an old, unused CRT monitor.

What is the greatest threat in this environment that could damage these memory modules?

A.The magnetic field around the CRT monitor

B.Electromagnetic interference (EMI) from the fluorescent lights

C.Electrostatic discharge (ESD)

D.High voltage discharge from the CRT monitor

Memory TroubleshootingAfter installing two memory modules, you power on the system to check for errors. You find that the BIOS program recognizes only one of the memory modules. What should you do first?

A)Change the memory timings in the BIOS to a slower (higher) settings

B)Make sure that both modules are seated properly in their slots

C)Return both modules for replacement

D)Reboot the computer and run memory diagnostic tests on the memory modules

You are in the process of configuring a new computer. The motherboard has four memory slots and supports dual channel memory. You install two memory modules. When you boot the computer, the BIOS recognizes both modules, but the memroy is not configured to run in dual channel mode. What should you do?

A)Add continuity modules to unused memory slots

B)Move the modules to the correct motherboard slots

C)Replace the memory with dual channel capable memory

D)Change the CAS latency to a higher setting

You are in the process of configuring a new computer. The motherboard has six memory slots and supports triple channel memory. You install two memory modules. When you boot the computer, the bIOS recognizes both modules, but the memory only runs in dual channel mode. What should you do? (Choose 2)

A)Move the modules to the correct motherboard slots

B)Install a third, identical memory module

C)Change the CAS latency to a higher setting

D)Replace the memory with triple channel capable memory

E)Add continuity modules to unused memory slots

You have just built a new system from scratch. You turn the computer on but the system boot fails and sounds with a beep code. What might the issue be?

A)Incompatible memory was installed

B)The system includes unsupported memory

C)Memory not installed or not detected

D)New and old memory has been mixed