Abit PX5 User Manual page 23

Installing the Mainboard
3. Maximum memory capacity 256M bytes supported by this
mainboard.
¡i Relationships between memory modules and Pentium
Computer
CPUs¡j
knowledge
Pentium, 6x86 and AMD-K5/K6 are all 64 bit CPUs, but 72-pin
SIMM modules are only 32-bit. That' s why they have to be used in
pairs, because the CPU will always be only able to see 64 bits. This
means that 72-pin SIMM modules have to be installed in pairs. The
two members of a pair must be of the same kind ¡i EDO or FP
DRAM¡j .
168-pin DIMM modules are 64 bit, so you can use single modules.
On the PX5 mainboard, these modules can support not only EDO
and FP DRAM, but also Synchronous DRAM memory
configurations.
When you install DIMM modules on the mainboard, you don' t have to setup
anything, just be sure that you use 3.3V unbuffered 168-pin DIMM modules, and
insert them in the memory socket.
Computer
¡i 168-pin DIMM modules specifications ¡j
Knowledge
According to the standards defined by JEDEC, there are a lot of
different types of specifications for 168-pin DIMM sockets. Here are
the possible types:
These types of DIMM modules differ not only by the electrical design,
but also by their architecture. So, if you buy different types of DIMM
modules, you will not be able to insert them in the DIMM sockets.
Currently, the standard for PC is 3.3V UNBUFFERED DIMM,
which is the standard supported by this series.
l 3.3V UNBUFFERED DIMM
l 3.3V BUFFERED DIMM
l 5V UNBUFFERED DIMM
l 5V BUFFERED DIMM
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