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Guide | Physical Installation Procedures ]
Memory Module Physical Installation Procedure
This procedure provides instructions for physically installing memory modules into a
motherboard. I include here instructions for installing both SIMM and DIMM
packaged memory. Installing memory modules can be a bit tricky, because SIMM sockets
especially are both delicate and sometimes difficult to use.
- Difficulty Level: 2-3 (Low to Moderate). Some SIMM sockets can be
extremely troublesome to use and it may take some patience to get the modules to install
properly. Others are easier to use. DIMM sockets are also easier to deal with.
- Risk Factor: 2-3 (Low to Moderate). It is possible to damage a SIMM
socket by trying to force a module into the socket incorrectly (but only if you are
impatient and force it). I have also received reports indicating the possibility of a
damaged motherboard if a module is inserted incorrectly.
- Hardware Required: A small, thin, flat-bladed screwdriver may be handy
in some cases.
- Software Required: None.
- Time to Perform: Less than 5 minutes
- Preparation / Warnings:
- If you have not already done so, please read the section on general
installation and assembly tips.
- This procedure assumes that the sockets are already empty and does not include
instructions for removing any modules that may already be present.
- Make sure that the motherboard is on a flat, clean, sturdy, static-free surface.
- Make sure that you are using the correct type of module for your system.
- For Pentium-class or later systems, 72-pin SIMMs must be used in identical pairs to make
up a bank; 168-pin DIMMs are used individually. For 486-class systems, 72-pin modules are
used individually and 30-pin modules in groups of four to make up a bank. If you need
assistance understanding the concept of a bank of memory, please refer to this page.
- This procedure assumes industry-standard SIMM sockets that are mounted to the
motherboard so that when properly installed, the SIMMs will be perpendicular to the
motherboard. There are some motherboards that have different types of sockets and the
instructions below would have to be improvised to suit these.
- Identify Installation Socket(s): Determine which memory module
sockets you are going to use for these modules. As usual, the best way to do this is to
consult your motherboard documentation; most motherboards will also physically label the
modules with numbered identifiers. For a new system, you will normally want to use the
first bank of memory on the motherboard, which normally means the lowest-numbered
socket(s). If you are installing more than one module, be sure to install them in the
correct order. This should be obvious by looking at the orientation of the sockets on the
motherboard. If you install them in the wrong order then you'll block off the second
socket with the first SIMM in most cases, and you'll have to remove and then reinstall
them in the correct order.
Warning: SIMM and DIMM sockets
are sometimes numbered staring with zero. This means that on a motherboard that takes
SIMMs, the first bank of memory may be "SIMM0" and "SIMM1". If you use
"SIMM1" and "SIMM2", you will be accidentally installing half a bank
of memory into each of the first two banks on the motherboard, and the system will not
- Orient Module: Line up the module next to the socket. Modules
are keyed to prevent incorrect insertion. The keying on the module itself is obvious, but
you may have to look very carefully at the socket to see which way the notch goes, and the
module itself may appear to be able to sit into the slot either way. Don't worry too much
about this; if you put the module in the wrong way you'll realize it as soon as you try to
tilt the module into place (it won't work).
- Insert Module: Insert the module into the socket. The instructions
depend on the type of module:
- SIMM: Hold the module at about a 60 degree angle to the motherboard and
then insert it into the socket. You will probably have to rock the module back and forth
slightly to get it to go in. Make sure that the module is seated all the way into the
bottom of the module; if it won't go all the way in, you may have it oriented backwards.
- DIMM: Firmly but gently push the module straight down into the socket.
It will not go all the way to the very bottom at this stage, but make sure it is pushed in
as far as it will go without requiring excessive force.
- Lock Module Into Place: The module will still be loose in the
socket at this point; it is not fully installed until you lock it into position:
- SIMM: Tilt the module up from the approximately 60 degree angle you
used when inserting it, to a 90 degree angle (perpendicular to the motherboard). This may
require a bit of pressure, but if the module will not tilt up at all, it is almost
certainly inserted either backwards or not all the way into the bottom of the socket. Do
not force the module. Pull it out and reinsert it if necessary; don't feel bad, this
happens to me all the time. After you tilt the module into place, you should see (and may
even hear) small metal or plastic clips snap into place around the module's circuit board,
on either side. Sometimes the clips don't snap properly and you may need to jimmy them a
bit to get them to tuck behind the SIMM; a small screwdriver may help here, but be careful
- DIMM: There should be a plastic lever on either end of the socket.
Grasp the lever and tilt it up. As you do this, the DIMM should be drawn down into the
socket. Tilt up both levers and the module should be installed.
- Double-Check Installation: It's sometimes hard to be sure that
modules are inserted correctly. The module should be securely and firmly in its socket. It
may wiggle a bit if you try to move it but it should not be loose. For SIMMs, there should
be clips on either side of the module holding it into the socket. The contacts should be
squarely inside the socket. If you have installed two identical modules, check their
height from the surface of the motherboard; it should be the same for both modules.
- Repeat If Necessary: Repeat steps 2 to 5 as necessary for each module
Physical Installation Procedure
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