So, you decided you want to upgrade. Now you need to figure out
what kind of RAM chips your computer has. Does the computer use single inline memory
modules (SIMMs) or dual inline memory modules (DIMMs)? If SIMMs, are they 30-bit or 72-bit
SIMMs? There are three ways to find out: check your manual, check by e-mail to our technical support team, or
pop the computers case open and have a look. The first choice requires little
explanation, so well focus on the other two.
Memory configurators. You can e-mail our technical support team with
the Manufacturer, Make and model of your computer and we will advise you on what kind of
memory your system requires.
Open up. The manual and memory configurator are handy if your computer
hasnt been upgraded before. If your computer is reporting a different amount of
memory than the manual says the computer shipped with or the memory configurators list as
the base configuration, you should pop the case open to check whether there are any open
slots for new memory modules.
Before you open your computers case, shut down your computer, turn it off, and
unplug it. Now youre ready to open the computer. Determine which screws, if any,
youll need to remove to slide the cover off. Some computers have no screws; you just
pull up on a couple of tabs and slide the cover off. If youre unsure which screws to
remove, consult your computers manual.
Once the cover is off, ground yourself by touching the computers metal case. Now
look for a series of slender 1-inch tall by 4-inch wide circuit boards; theyre
probably green with small black chips attached. Usually, the RAM chips are near the
central processor (the huge chip with a fan or large block of metal on top of it). If you
cant find the chips, look for four identical empty sockets-on some computers, the
factory-installed RAM is soldered onto the motherboard, not in the sockets. If the sockets
are empty, itll make upgrading a breeze; youll just need to check your manual
or a memory configurator for the type of RAM to order and then pick the amount you want.
Once you find the memory chips, you can make a list of what you have installed. If there
are no empty sockets, dont worry. Youll just have to remove some old modules
to make way for new, bigger ones. Dont immediately rip out the old modules, however,
because they can tell you a little about what kind to order.
You can tell by the number of pins what type of memory you have. The three major types of
memory chips are: 30-pin SIMMs (used with 386-series processors), 72-pin SIMMs (used with
486-series and some Pentium processors), and 168-pin DIMMs. SIMMs can differ not only in
terms of pins, but whether they are parity or non-parity SIMMs. You can tell the
difference by counting the number of chips on a SIMM. SIMMs with 2, 4, 8, or 16 chips are
non-parity SIMMs; those with 3, 6, 9, 12, or 18 chips are parity SIMMs. You dont
want to install parity and non-parity SIMMs in the same PC.
When selecting SIMMs, you also need to check the
access speed and Extended Data Output (EDO) compatibility. Make sure the access
speed of the SIMMs or DIMMs youre buying meets the PCs minimum
requirements by either checking the manual, by e-mail, or the old module. The speed is
denoted on each memory chip of a module with the last number in a series of letters and
numbers. For example, 4P1024DJ-07 indicates an access speed of 70 nanoseconds (ns).
If you have a Pentium processor, youll also need to check your manual or a memory
configurator to see whether your computer requires EDO memory chips. If
you install non-EDO chips, the computer might not boot up. If it does boot, it will run
slower than if you had installed EDO chips.
Place Your Order & Install
Now, you can figure out what size modules you
must order. You have two options: You can keep some of the modules and replace others or
replace all of them. Youll have to figure out the math to see what kind of
configurations you can have. Just remember that with Pentium processors that use SIMMs,
you have to install the SIMMs in pairs (for example, two 16MB SIMMs and two 4MB SIMMs). On
the other hand, 386 processors require sets of four 30-pin SIMMs, but can support single
72-pin SIMMs. On 486 and Pentium II processors, you can install single memory modules.
Modules: vertical and slanted for SIMMs, and DIMM for DIMMs. Since you might have to
remove old memory chips to replace them with new ones, well explain how to install and
remove modules from these sockets. If there aren't already SIMMs in the slots, you can
tell whether they're slanted or vertical by looking for the retaining clips. If they're
about a quarter-inch behind the socket, the socket is slanted. If the retaining clips are
to the immediate right and left of the socket, it's vertical.
Before you remove any RAM chips from their plastic packaging, touch the computers
case to ground yourself and discharge static electricity.