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RAM - (Random Access Memory) Usually described
in terms of how many Megabytes (Meg or MB). This is the type of memory used
in personal computers today. Older computers usually have 16-32 Meg ram
installed in them. Newer computers frequently have from 64-256 Meg of ram
installed in them. Why do people need to add more RAM to their
computers? Because if a computer doesn't have enough RAM (chips) the
computer will use the hard drive to manage data during processing instead of
memory chips. Since memory chips are substantially faster than a hard drive,
if the computer runs out of available space on the memory chips, then the
entire system will slow down to the speed of the computer's hard drive, which
causes a substantial decrease in performance of the computer regardless of
the speed of the hard drive. How do I know if I need more RAM? This answer is a
little complicated. A general rule is that more is better unless you already
have plenty. The fact is, if you don't need more RAM, then adding more RAM
will not speed up your PC. But, if too little RAM in your system is causing a
'bottle-neck', then adding more RAM will surely speed up you PC. More
specific examples of when to add memory follow: a. If you're running Windows XP, you will
need at least 128MB, but you'll run much smoother with 256MB. If you are
running windows 98 or Windows ME on your computer then you should have at
least 32MB but you computer will almost surely run faster if you have 64MB,
although 128MB is best. 256MB couldn't hurt especially if keep several
programs open at once or if you are a heavy gamer. b. If you are running windows 95 on your
computer then you should have at least 32MB. If you have any less than 32,
then adding more RAM will almost definitely speed up your system. 64MB to
128MB is recommended. c. If you are running Windows 3.1X then you
should have at least 16MB RAM, but 32MB may speed things up for you. Look for
the flickering hard drive light on the front of your PC (see below). d. If you are running Windows NT workstation
or Windows 2000 Professional, then you should have at least 64MB, but 128MB
or 256MB is much more common and will certainly speed up your system. e. If you PCs HDD (hard disk drive) light
flickers a lot during standard processing, you almost definitely need more
RAM. This is an indication that the computer is running out of available
space on your memory chips, so it is therefore relying more heavily on the
swap disk portion of your hard drive to process data. Since your hard drive
is much slower than your RAM chips, your entire computer system is slowing
down to the speed of your hard drive. Adding more RAM will allow your PC to
perform more processing entirely within the RAM chips and that will speed up
your computer. f. The System
Resources of Windows 9X, ME or 2000 indicates less than 65%. Right click on
the MY COMPUTER icon, scroll down to properties and then click on the
PERFORMANCE tab. Check the % of available resources that are free. g. Windows 3.1x indicates
less than 70% free. From the Program manager, click on HELP (from the menu
bar) and then click ABOUT. h. You multitask a
lot of programs at the same time in Windows. If you use several utilities and
programs simultaneously having extra memory will increase performance. I. You receive error messages indicating
that you don't have enough memory. i. You don't
need more memory if you already have plenty. If memory is not a bottleneck in
your system then adding more will not increase performance. Spend your money
on something else. Some definitions SIMM - (Single In-line Memory Module) These are
circuit boards that have memory chips soldered on to them. They are usually
installed in groups or 'banks'. SIMMs usually come
in two major types. 30-Pin and 72-Pin. A 30-pin SIMM measures about 3 inches
and a 72-pin SIMM is about 4 inches long. 72-pin SIMMs have
the value of 4 30-pin SIMMs. For example, four 1Meg 1X8 30-pin SIMMs, (which
has 8 data bits), is equivalent to one 4 Meg 1X32 72-Pin SIMM, (which has 32
data bits). DIMM - (Dual In-line Memory Module) Similar to
SIMMs but the arrangement is slightly different. DIMMs
have the value of 2 SIMMs and are therefore added individually (not in
pairs). The DIMMs commonly used in PCs today have
168 pins (count them if you want). DIMMs generally
use Synchronous DRAM and are therefore referred to as SDIMMs.
Fast Page Mode (FPM) - The standard
variety of RAM that has been in use for many years. Also known as 'regular'
or 'non-EDO' to the less informed. PINS - The number of
contacts on a memory module that make contact with the SIMM socket. Try
counting them if you wish. Parity and Non
Parity - Refers to additional bits of memory on a SIMM module. Parity
checking is a method of verifying the integrity of the computers data. Some
computers perform parity checks during data processing. Logical Name - The industry
descriptor used to identify value of a memory the module. Examples are
8X32-60 (32Meg 72-pin SIMM) or 4x64 (32Meg DIMM). Here is a guide to
understanding this nomenclature. 168-pin DIMMs - There are 32 Meg,
64 Meg, 128 Meg, 256 Meg and 512 Meg DIMMs in
popular use. They are identified as somethingX64 (non-ECC) or somethingX72
(with ECC). The sixty-fifth through the seventy-second bits are the ECC bits.
The formula to determine the megabytes on a DIMM is (xXn)/8
for non-ECC and (xXn)/9 for ECC DIMMs.
For example, a 16x64 DIMM is equal to 128 Meg. (16x64=1024, 1024/8=128). 72-pin SIMMs There are 4 Meg, 8
Meg, 16 Meg 32 Meg and 64 Meg SIMMs in popular use. They are identified as a
somethingX32 (non-parity) or somethingX36 (parity). The thirty-third through
the thirty-sixth bits are the parity bits. The formula to determine the
amount of memory on a 72-pin SIMM is (xXn)/8 for
non-parity and (xXn)/9 for parity SIMMs. For
example, a 2X32 SIMM is equal to 8 Meg. (2X32=64, 64/8=8). 30-pin SIMMs There are only 1
Meg and 4Meg 30-pin SIMMs in popular use. They are identified as a
1Xsomething or a 4Xsomething. There are non-parity, (1X8), and parity, (1X9),
versions of these SIMMs. The ninth bit is the parity bit. Another convention
of naming the SIMMs is to identify the number of chips on a 30-pin SIMM.
Therefore a 1X3 is just like a 1X9 except that it uses 3 chips to make the
same thing. The three chip SIMMs are comprised of two chips which have the
value of 4 each, totaling 8, and one more chip to make the ninth (parity)
bit. These SIMMs are functionally and logically equivalent to a 9-chip SIMM
and can be used in place of a 9-chips SIMM in almost
all cases. Sorry, but we don't sell 30-pin SIMMs anymore. Why? Because
no one makes them anymore. NS - Nanoseconds. The -60, -70 or -10 number
at the end of each logical descriptor refers to the rated nanosecond speed of
the module. The lower the number the faster the rating of the SIMM or DIMM
module. How do I know what type and
quantity of memory modules I should buy to upgrade my computer? This is by far the
most difficult question for most end users. There are several keys to
determining what you need. Here is a handy upgrade guide. It will hold true
in almost all cases, although there are certain non-standard types of system
designs which may not conform to this guide. a. Check your users
manual. Most manuals will have a chart indicating the various
combinations of modules that are appropriate for your PC. If you can't
decipher this chart, just bring your manual in to PCs for Everyone and we
will help you read it. b. Check the memory modules in your PC. What
is already there will usually indicate what you must buy. Open up your system
and look for some sign of the type of memory module. Many module
manufacturers will clearly indicate the type, the megabyte size, and the
speed of the module. There may also be some indication of whether the type of
RAM chips used on the module, such as SDRAM, EDO RAM, Fast-Page RAM, etc.
Additional RAM features such as parity, ECC and buffering may be indicated as
well. b. Depending on the processor-type of
your PC, you can figure out what you need. To find out what your
'processor' (CPU) is, either check your user's
manual or the invoice for your PC. Almost all PCs will tell you the processor
type during boot up. As the system is turning on you will most likely see a
BIOS screen. Press the 'pause' key on your keyboard when the BIOS screen
appears. This will allow you to take your time to study the information
provided. Does it mention the processor/CPU type? Keep in mind that you can usually
substitute faster RAM for slower RAM (about 98 percent of the time) and
then under-clock the memory module. This circumstance will often happen
because your system is getting on in years (we usually equate 1 human year to
20 computer years), and RAM and module manufacturers may no longer produce
the exact memory product for your PC any longer because the demand has
subsided. So, for example, if your PC needs PC66 SDRAM, you can probably use
PC100 modules set to run at 66MHz. |
