What Types of PC Memory are There to Choose From?
So you're looking for PC memory to upgrade your system with, but aren't
quite sure what you're looking for. Hopefully we can help you with some
information about the various types of memory that are available to
choose from.
The first type of memory to see widespread use is the 72-pin
SIMM(http://www.oempcworld.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=72pin).
Unlike the 30-pin SIMM that preceded it, the 72-pin version had a 32-bit
data bus, requiring only one or two memory modules to fill the system's
data bus, as opposed to the four or eight 30-pin SIMMs that had been
required before that. The 72-pin SIMM these days will need to be
installed in pairs, as almost all systems have a 64-bit data bus, and
come in sizes ranging from 8MB to 128MB of memory. So if you want to add
only 128MB of PC memory to your system, remember to get two 64MB memory
modules(http://www.oempcworld.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=64M-EDO).
Otherwise, make sure what type of 72-pin SIMM you need, as there are two
formats - FPM (Fast Page Mode) and EDO (Extended Data Out), and not all
motherboards will work with both types, not to mention that you will
need to make sure that if you are adding RAM to your system, you install
the same type as is already being used.
The replacement for the 72-pin SIMM PC memory is the 168-pin
SDRAM(http://www.oempcworld.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=168pin).
The 168-pin SDRAM has a few advantages over the 72-pin SIMM, but the
greatest advantage is the 64-bit data bus used by the memory. This means
that each module communicates with the system's data bus without needing
to pair memory together, and allows for upgrading the memory one piece
at a time. In addition, SDRAM operates at a higher speed then 72-pin
SIMMs, operating at
66MHz(http://www.oempcworld.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=PC66),
100MHz(http://www.oempcworld.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=PC100)
or
133MHz(http://www.oempcworld.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=PC133).
The size of memory available in 168-pin SDRAM varies widely, from
32MB(http://www.oempcworld.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=32M-PC100)
up to
1GB(http://www.oempcworld.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=1.0G-PC133)
modules. The most common sizes in use these days are
256MB(http://www.oempcworld.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=256M-AP133)
and
512MB(http://www.oempcworld.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=512M-PC133).
