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How
to identify the size of RAM modules?
Question
You
have purchased a large collection of RAM modules - SIMMs and DIMMs
- that you want to resell, but you have no idea of how to identify
the memory capacity in megabytes (MB) of the individual modules,
and you want to know if there is any way to determine the size
of a module other than by installing it on a motherboard in a
computer that supports that type of RAM.
Answer
It
is possible to identify the chips by part number. You have to
identify the size of each the chips on a module, and then multiply
the size by the number of chips on the module to determine its
memory capacity.
Different
RAM manufacturers have developed their own methods of identification,
so it is has become difficult to identify the chips without looking
up the exact part number on a website that provides the information.
Luckily,
the Internet has made doing this fairly easy via the Google
search engine.
Unless
they have been remarked by unscrupulous dealers that are selling
substandard modules not passed for use in a computer as computer-quality,
all of the chips on a particular module will have the manufacturer's
name (or logo), and a part number printed on them.
For example, a 30-pin SIMM module with nine chips on the module,
could have the part number - KM41C4000AJ-8. Drop the AJ-8
(the first letter is usually the quality - A, B, C, etc.),
then use KM41C4000 to conduct a Google
search. You should be provided with links to many sites that provide
information about part numbers. One of them is http://www.memoryusa.com/guide.html.
The
KM indicates parts made by Samsung. The 41
indicates that it is a 1Mbit x 4 part. This means that the chip
holds 4Mbits. Eight of the nine chips hold memory, so this is
a 8 x 4Mbit, or 32Mbit module. There are eight bits to a byte,
therefore this is an 4MB module. The ninth chip is there to add
parity. This was used as a means of checking for memory errors
that is no longer used.
For
a 168-pin DIMM module that has eight chips (no parity chip), and
the part number - TMS626812DGE-12A - you would use TMS626812
to search for information on it.
Each
chip is a 2Mbit x 8 (16Mbit) SDRAM chip. There are eight chips,
so this is a 16MB SDRAM module, which is slow compared to the
fastest speed that SDRAM modules reached. The 12 in the
part number indicates that the module has a maximum frequency
(speed) of 66MHz. SDRAM modules, now superseded by DDR and Rambus
RAM, reached a maximum speed of 133MHz.
Decode
RAM chip part numbers
At the
following site, you just enter the RAM chip part numbers to find
out the manufacturer and specifications. -
http://www.chipmunk.nl/DRAM/ChipManufacturers.htm
Windows
2000
According
to received opinion, this is the situation at present.
Windows
2000 needs at least 128MB of RAM to work properly.
More RAM comes in handy when multitasking in Windows 2K. The Council
on Computing Power has launched a new Windows 2000
info-site, with articles, studies and more...
Windows
XP
Windows
XP, Microsoft's latest 32-bit series of operating systems
for both the home and dedicated server and workstation networking
has a recommendation of a minimum system requirement of 128MB
of RAM, with 256MB preferred.
Indeed,
I have just read a Crucial Technology newsletter that recommends
320MB of RAM to run the standard version of the Office XP suite.
A bit of eye-opening information, since high-end PCs costing £2000
usually only come with 256MB.
DDR
SDRAM and Rambus RAM --
What is RAM and what does it do? -- Which
DDR RAM? -- How to install RAM?
-- How to identify the size
of RAM modules? -- Different types of
RAM? -- Mixing brands can often cause
problems -- Memory Frequently Asked
Questions
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