|
TOOLS HOME
- ULTIMATE MEMORY GUIDE
- PERFORMANCE STUDIES
- MEMORY ASSESSOR
- DIGITAL MEDIA GUIDE †
- DDR WHITE PAPER †
- MANUFACTURING VIDEO †
† These links go directly to Kingston U.S. website.
|
|
 |
Ultimate Memory Guide
WHAT TO CONSIDER WHEN BUYING MEMORY
One of the quickest and easiest ways to identify the right memory modules and
expansion options for your computer is to use a memory configurator. Like some
of the other major memory manufacturers, Kingston makes a memory configurator
available. You can access Kingston's configurator through their home page at
www.kingston.com.
The most important thing to ensure when buying memory is compatibility with
your system. In addition, you'll need to decide how much memory you need and
beyond that lie considerations of price, quality, availability, service, and warranty.
This section helps you address these important decision factors and helps you
answer questions like these:
- How much memory do I need?
- How much memory will my system recognize?
- What kind of memory is compatible with my system?
- How many sockets are open and how should I fill them?
- How do I determine the quality of memory?
- What should I know about memory prices?
- What other issues should I consider?
COMPATIBILITY
As mentioned earlier, compatibility of memory components with your computer
system is arguably the most important factor to consider when upgrading memory.
This section can get you started; it also makes frequent mention of the advantages
of using a memory configurator.
WHAT KIND OF MEMORY IS COMPATIBLE WITH MY SYSTEM?
The easiest way to determine what type of memory goes with your system is to
consult with your system documentation. If you need further assistance, consult a
memory configurator available from many sources, including Kingston. Kingston
and other brand-name memory companies offer such a tool to help you find the
right memory configuration for your system.
With Kingston's configurator, you can search by five different criteria:
- System manufacturer/model
- Computer model name
- Memory module part number (Kingston, distributor, manufacturer)
- Specification
- Generic memory
To access Kingston's Memory Configurator, click here
WHAT IF I CAN'T FIND MY SYSTEM IN A MEMORY CONFIGURATOR?
If you can't find your system in the memory configuration programs, you can still
find out what kind of memory you need by consulting the manual that came with
your system. In most cases, the manual will provide basic specifications such as the
speed and technology of the memory you need. This information is usually enough
to choose a module by specification. If you don't feel you have enough information,
you can call your system manufacturer or Kingston's toll-free technical support
number for assistance.
HOW MANY SOCKETS DO I HAVE OPEN?
You may or may not have an idea what the inside of your computer looks like and how
memory is configured. You may have opened up your computer when you bought it to
see the configuration inside, or you may have looked at a configuration diagram in your
user's manual. Even if you have no idea of the memory configuration of your system,
you can use Kingston's memory configuration tools to find out. For each system, the
configuration includes a diagram, called a bank schema, which indicates how the
memory sockets are arranged in your system and what the basic configuration rules are.
The simple tutorial on the next page outlines how to use a bank schema diagram to
determine the number of sockets in your system and how to fill them.
HOW TO READ A BANK SCHEMA
A bank schema is a diagram of rows and columns that shows the number of
memory sockets in your system. This diagram is a theoretical bank layout and not
an actual system board layout; it is designed to help you quickly determine configuration
requirements when adding memory modules.
In a bank schema, each [__] represents a memory socket:
Example: [__][__][__][__] = 4 memory sockets
Each column in the diagram represents a memory bank. The number of "[__]"
symbols in a column represents the number of memory sockets in a bank.
Upgrading is performed one bank at a time. For example, if there are four columns
with two [__] in each column, upgrading is done two modules at a time. However,
if there is just a single row of [__], upgrading may be performed one module at a time.
Examples:
8 sockets = [__][__][__][__][__][__][__][__]
(Modules may be installed one at a time in any combination)
| 8 sockets (4 banks of 2) = |
 |
(Modules must be installed two at a time)
| 4 sockets (1 bank of 4) = |
 |
(Modules must be installed four
at a time) |
The standard memory (base amount that the system was shipped with) appears in
the diagram as either removable or non-removable.
Removable memory comes in the form of modules that fit into memory sockets,
and, if desired, can be removed and replaced with modules of higher capacity.
Removable memory is represented by a " "
symbol with a number next to it: 4
[___] indicates that a 4MB module is in the first socket and that the second socket is empty.
Non-removable memory usually comes in the form of memory chips soldered
directly onto the system board. It is represented in the bank schema in brackets:
[_4MB_] indicates 4MB of non-removable memory soldered onto the board and two available
memory sockets.
If your system is not included in the configurator, you may be able to find out how
many sockets are in the system and how many are filled by pressing the F1 key during
system startup. If your system supports this, a screen will appear that indicates how
many memory sockets are in the system, which ones are filled and which are open, and
what capacity modules are in each socket. If pressing the F1 key during startup doesn't
produce this result, check your computer's system manual for more information.
As a last resort, you can open your computer and take a look at the sockets.
(Important Note: Before removing the cover of your computer, refer to the
computer's system manual and warranty information for instructions and other
relevant information.) If you do open the computer, you may be able to identify
"bank labels" that indicate whether memory are installed in pairs. Bank numbering
typically begins with 0 instead of 1. So, if you have two banks, the first bank will
be labeled "bank 0", and the second bank will be labeled "bank 1."
HOW SHOULD I FILL THE SOCKETS?
In most cases, it's best to plan your memory upgrade so you won't have to remove
and discard the memory that came with the computer. The best way to manage this
is to consider the memory configuration when you first buy the computer. Because
lower-capacity modules are less expensive and more readily available, system
manufacturers may achieve a base configuration by filling more sockets with
lower-capacity modules. By way of illustration, consider this scenario: a computer
system with 64MB standard memory comes with either two (2) 32MB modules or
one (1) 64MB module. In this case, the second configuration is the better choice
because it leaves more room for growth and reduces the chance that you'll have to
remove and discard lower-capacity modules later. Unless you insist on the (1) 64MB
module configuration, you may find yourself with only one socket left open for
upgrading later.
Once you have purchased a computer and are planning your first upgrade, plan to
buy the highest-capacity module you think you may need, especially if you only
have one or two sockets available for upgrading. Keep in mind that, in general,
minimum memory requirements for software applications double every 12 to 18
months, so a memory configuration that's considered large today will seem much
less so a year from now.
QUALITY
As with any type of product, memory can vary in the quality from one manufacturer
to another. In general, the larger, more established brand name companies are more
consistent in adhering to tight design specifications, using high-quality components,
and establishing certified quality control processes for manufacturing and thorough
testing. That's not to say that lower-quality modules don't work fine - they may be
the right solution, depending on how hard you work your system. In deciding the
level of quality you require, consider the following:
- If the memory you buy doesn't perform well, will you be comfortable returning
it for a replacement? Would you have the time to deal with removing the
memory and waiting a couple of days to a week to get the situation resolved?
- When memory is of low quality, you often experience intermittent problems,
such as the computer "freezing" unexpectedly, or having frequent errors. How
often do you save your work, and if you were to lose your work, how much
would that cost you? If you use your computer to play games, read email, and
surf the Internet, such interruptions and losses may not be a big problem. But if
you're running a business, losing a few hours of work could be a serious matter.
- The biggest risk with unreliable memory is data corruption: that is, some bits
of data may change or be read incorrectly. The result of data corruption could
be as harmless as a syntax error in a document, or as potentially serious as a
miscalculation in a spreadsheet. How important is the accuracy of the work
you do on your computer? Again, if you use your computer for gaming, writing
letters, and the Internet, it may not be a problem. But if you're managing your
finances, you may want to do all you can to assure the reliability of your data.
- Just like all products, the quality and durability you require depends on how
you use it. Computer applications that require a lot of memory usually work
the memory very hard. These applications often work better with memory that
exceeds the system's speed and reliability specifications. If you're working in
multimedia or using heavy number-crunching programs, the chance of a
lower-quality memory module failing is greater than if you're only doing light
work, such as simple word processing.
ASSESSING MEMORY QUALITY
Here are some important factors to keep in mind when assessing the quality of a brand of memory:
DESIGN
Designers of memory modules can follow strict specifications or take short cuts to
save money on components. In general, manufacturers who do in-house design have
more control over the quality of the module than those who farm this work out.
COMPONENTS
The quality of the DRAM chips, PC boards, and other components used on the
module are critical to the overall quality of the module. Premium memory chips
can cost up to 30% more than low-grade chips and high-quality PC boards cost
about 50% more than lower quality alternatives.
ASSEMBLY
Many factors in module assembly can affect the overall quality of the module. In
addition to proper handling of components, solder quality affects how reliably
information can travel from the chip to the module and back. The temperature and
humidity in the assembly and storage areas must be regulated to prevent warping,
expansion, and contraction of components during assembly.
PROPER HANDLING
Electro-Static Discharge (ESD) is one of the most common causes of damage to
a memory module. ESD damage can result from excessive and inappropriate handling.
Memory modules should only be handled by workers who are properly "grounded" and
modules should be properly packaged to protect against ESD during shipping.
TESTING
The more thoroughly memory has been tested before it is shipped, the less chance of
problems during operation. In addition to standard production tests to ensure that the
modules have been built correctly, memory can be tested for compatibility in the
systems in which it will be used. The DRAM core can be tested for chip reliability, and
modules can be tested "at speed" to make sure they will work in high-use situations.
Some companies perform testing at all levels, and some do less testing.
PRICING AND AVAILABILITY
This section contains information that helps make sense of the fluctuations that can occur in the memory market.
THE DRAM CHIP MARKET
Memory modules are made with DRAM chips, which are manufactured in mass
quantities in enormous fabrication plants (often referred to as "fabs"). Fabs can take
up to two years to build and require substantial capital investment: approximately
$3 billion per plant. These time and cost factors directly affect on the ability of the
memory market to adjust quickly to fluctuations in supply and demand. When
demand for memory chips increases, chip manufacturers typically do not respond
immediately because the investment required to add more capacity is substantial
and may not pay off, especially if all the competitors are doing so at the same time.
Therefore, the immediate effect is that prices rise as manufacturers assess whether
the increase on demand is temporary or substantial enough to warrant investment.
By the same token, when there is an oversupply situation in the market, chip
manufacturers are willing to sustain losses for a long time while prices fall to below
breakeven levels. This is because in many cases it costs more money to shut a plant
down than to continue to produce and sell chips at below cost. Also, the longer a
manufacturer can hold on, the greater the chance of "being there" to reap the
rewards when competitors reduce capacity and the market turns around again.
WHY MEMORY PRICES FLUCTUATE
There are several factors that can affect memory prices. A few of these include:
demand, DRAM manufacturing levels, inventory in the marketplace, time of the
year, new operating system releases, and computer sales. All these things can affect
memory prices at different times, either separately or simultaneously.
The most important thing to keep in mind when buying memory is that the price
of 256MB today will most likely be different than the price of 256MB next quarter.
The best rule of thumb is to compare memory prices close to your time of
purchase. When doing price comparisons, it's more important to make sure you are
making equivalent comparisons on module types than how the actual price per MB
varies over time. If there are shortages in the market it's most important to be sure
that what appears to be a "great deal" isn't a "short-cut" module built from off-spec
components. In an oversupply market, you're much more likely to get a great price,
but keep in mind that many manufacturers are losing money and may take shortcuts
on testing and other expensive production quality measures to compensate. Refer
to the quality section above for more details on this.
|
|
