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Technical 
Memory Problems
Memory Problems
COMMON MEMORY PROBLEMS
When you have a problem with memory, the cause is usually one of three
things:
Improper Configuration: You have the
wrong part for your computer or did not follow the configuration rules.
Improper Installation: The memory may not be seated correctly,
a socket is bad, or the socket may need cleaning.
Defective Hardware: The memory module itself is defective.
The fact that many computer problems show themselves as memory problems
makes troubleshooting difficult. For example, a problem with the motherboard
or software may produce a memory error message.
BASIC TROUBLESHOOTING
The following basic steps apply to almost all situations:
1) Make sure you have the right memory component for your computer.
At the manufacturer's Web site you can look up the part number. Many
memory manufacturers have configurators, which indicate the compatibility's
of your module. If not, phone the memory manufacturer, consult your computer
manual, or phone the computer manufacturer.
2) Confirm that you configured the memory correctly. Many computers
require module installation in banks of equal-capacity modules. Some computers
require the highest capacity module to be in the lowest labelled bank.
Other computers require that all sockets be filled; still others require
single-banked memory. These are only a few examples of special configuration
requirements. If you have a name-brand computer, contact technical support
for your memory or computer manufacturer.
3) Reinstall the module. Push the module firmly into the socket.
In most cases you hear a click when the module is in position. To make
sure you have a module all the way in the socket, compare the height of
the module to the height of other modules in neighbouring sockets.
4) Swap modules. Remove the new memory and see whether the problem
disappears. Remove the old memory, reinstall the new, and see whether
the problem persists. Try the memory in different sockets. Swapping reveals
whether the problem is a particular memory module or socket, or whether
two types of memory aren't compatible.
5) Clean the socket and pins on the memory module. Use a soft cloth
to wipe the pins on the module. Use a PC vacuum or compressed air to blow
dust off the socket. Do NOT use solvent, which may corrode the metal or
prevent the leads from making full contact.
6) Update the BIOS. Computer manufacturers update BIOS information
frequently and post revisions on their Web sites. Make sure you have the
most recent BIOS for your computer. This applies especially when you have
recently installed new software or you are significantly upgrading memory.
WHEN THE PROBLEM OCCURS
When the problem occurs is a clue as to the cause.
For example, your response to a memory error message depends on whether:
1) You have just bought a new computer.
2) You have just installed new memory.
3) You have just installed new software or a new operating system.
4) You have just installed or removed hardware.
5) Your computer has been running fine and you've made no
other recent changes.
This are rules to get started:
YOU'VE JUST BOUGHT A NEW COMPUTER
If you have just purchased a new computer and it is producing memory errors,
the problem could be related to anything, including a bad computer board.
In this case, you need to troubleshoot the entire computer, including
memory. Because the computer dealer will have configured memory and run
system tests before shipping, they can best help.
YOU'VE JUST INSTALLED NEW MEMORY
If you have just installed new memory, the first possibility is that you
installed incorrect parts. Double-check the part numbers. Confirm that
you have configured and installed the memory correctly.
YOU'VE INSTALLED NEW SOFTWARE OR OPERATING SYSTEM
Newer software or operating systems tend to push memory harder than older
operating systems. Sometimes memory that worked fine prior to a software
installation begins producing errors once it runs memory-intensive software.
New software also has bugs, and beta versions are notorious for producing
memory errors. In these cases, your first step should be to ensure you
have the latest BIOS and service patches for your software. Otherwise
contact the memory vendor. A technical support representative may have
experience with other software incidents and can walk you through more-detailed
troubleshooting.
YOU'VE INSTALLED OR REMOVED HARDWARE
If you have just installed or removed hardware and suddenly receive memory
error messages, the first place to look is in the computer itself. A connection
may have come loose during the installation or the new hardware may be
defective; in either
case the errors are manifesting themselves as memory problems. Make sure
you have the latest drivers and firmware. Most hardware manufacturers
will post updates on their Web sites.
UNEXPECTED PROBLEMS
If your system has been running fine, but suddenly starts to produce memory
errors, and crash or lock up frequently, the chance of a hardware failure
is more likely, since configuration and installation problems show up
as soon as the computer turns on. Sometimes you can get memory problems
if your computer is overheating, if you are having a problem with your
power supply, or if corrosion has developed between the memory module
and the socket, weakening the connection.
HANDLING SPECIFIC PROBLEMS
Here is a list of the most common ways the computer informs you of a memory
problem.
1) The computer won't boot, merely beeps.
2) The computer boots but doesn't recognise all the installed
memory.
3) The computer boots but the screen is blank.
4) The computer reports a memory error.
- a) Memory mismatch error
- b) Memory parity interrupt at xxxxx
- c) Memory address error at xxxxx
- d) Memory failure at xxxxx, read xxxxx, expecting xxxxx
- e) Memory verify error at xxxxx
5) The computer has other problems caused by memory.
- a) The computer intermittently reports errors, crashes frequently,
or spontaneously reboots.
- b) Registry Errors
- c) General-protection faults, page faults, and exception errors
6) The server system manager reports a memory error.
The following translations help you understand what the
computer means when it gives you one of these signals.
1) Computer won't boot, merely beeps.
Every time the computer starts, it takes inventory of hardware. Inventory
consists of the computer BIOS recognising, acknowledging, and in some cases,
assigning addresses to, the components in the computer. If the computer
won't
boot, the CPU is unable to communicate with hardware. The cause can be improper
installation or failure of the BIOS to recognise hardware. Follow basic
troubleshooting, paying special attention to whether the memory module is
completely installed and that you have the latest version of the BIOS.
2) Computer boots but doesn't recognise all the installed memory.
When the computer boots, a part of the process is counting memory. On some
machines the count appears on the screen and on others is masked. If the
count is masked, from the computer set-up menu see how much memory the computer
thinks it has. If the computer counts to or lists a number less than the
memory you installed, the computer hasn't recognise all the memory.
Sometimes the computer will recognise only part of a module. This is almost
always due to using the wrong kind of memory. For example, if your computer
accepts only single-banked memory and you have installed dual-banked, the
computer will read only half the memory on the module. Sometimes the computer
will accept only modules containing memory chips with specific organisation.
For example, the VX chipset doesn't work well with 64 Mbit chips. In
many computers the maximum amount of memory the computer can recognise is
lower than the maximum amount you can physically install. For example, your
computer may have three sockets, each of which can hold a 128 MB module.
If you filled every socket with 128 MB, you would have 384 MB of memory.
However, your computer may recognise a maximum of 256 MB. In most cases
you can avoid this problem by consulting your computer manual or a memory
configuration Web site before purchasing memory.
3) The computer boots but the screen is blank.
The most common reason for a blank screen is a dislodged card, memory not
fully seated, or memory the computer doesn't support. Confirm that
the memory is installed properly and that other components in the computer
were not accidentally disconnected or dislodged while you installed memory.
Double-check that you have the right part number for the computer. If you
have non-party memory in a computer that requires error-checking memory,
or SDRAM memory in a computer that supports only EDO, the screen may be
blank at boot up.
4) The computer reports a memory error.
Memory mismatch error: This is not actually an error. Some computers require
you to tell them that it's OK to have a new amount of memory. Use the
set-up menu to tell the computer. Follow the prompts, enter the new amount,
select Save, and exit. Computer memory or address errors: All of the following
errors, and those similar to them, indicate that the computer has a problem
with memory:
- Memory parity interrupt at xxxxx
- Memory address error at xxxxx
- Memory failure at xxxxx, read xxxxx, expecting xxxxx
- Memory verification error at xxxxx
Typically the computer will perform a simple memory test as it boots.
The computer will write information to memory and read it back. If the
computer doesn't get what it was expecting, then it will report an
error and sometimes give the address where the error occurred. Such errors
normally indicate a problem with a memory module but can sometimes indicate
a defective motherboard or incompatibility between old and new memory.
To verify that the new memory is causing the problem, remove the new memory
and see whether the problem goes away. Then remove the old memory and
install only the new memory. If the error persists, phone the memory manufacturer
and ask for a replacement.
5) The computer has other problems caused by memory.
The Computer Intermittently Reports Errors, Crashes Frequently, or Spontaneously
Reboots: Because of the large number of causes, these problems are difficult
to diagnose. Possible causes are ESD (Electrostatic Discharge), overheating,
corrosion, or a faulty power supply. If you suspect ESD damage, contact
the memory manufacturer and ask for a replacement. If you suspect the
power supply, you will have to do overall computer troubleshooting with
a focus on the power supply.
Registry Errors: Windows writes a large portion of the registry to RAM.
Sometimes defective memory will cause registry errors. Windows reports
a registry error and prompts you to restart and restore. If the prompts
repeat, remove your newly installed memory and restart the computer. If
the errors disappear, ask the memory manufacturer for replacement modules.
General-Protection Faults, Page Faults, and Exception Errors: The most
common cause is software. For example, one application may not have released
the memory after quitting or occupies the same memory addresses as another.
In these cases, rebooting should solve the problem. If the computer suddenly
displays general-protection faults, exception errors, or page faults after
you have installed new memory, remove the new memory and see whether the
errors stop. If they occur only when the new memory is installed, contact
the memory manufacturer for assistance.
6) The server system manager reports a memory error.
Most servers ship with system managers that monitor component utilisation
and test for abnormalities. Some of these system managers count soft errors
in memory. Soft errors have been corrected by ECC memory. If the rate
of soft errors is higher than specifications, however, the system manager
issues a pre-failure warning. This warning enables the network administrator
to replace the memory and prevent system downtime.
If the system manager on your server issues a pre-failure warning or other
memory error, ask your memory manufacturer for a replacement. If the system
manager continues to issue errors after memory replacement, make sure
you have the latest BIOS, software service patches, and firmware. The
chance of receiving two bad memory modules in a row is low. Contact the
memory manufacturer for compatibility troubleshooting. Sometimes the server
does not work well with certain types of memory chips or certain memory
designs.
| Originally from http://www.kingston.com
- Ultimate Memory Guide |
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