System Memory Configuration
The PR5 is designed to provide the broadest possible
memory configuration options. The design includes four
sockets for the currently most common form factor, 72-
pin SIMM modules and also has two sockets for the fu-
ture standard, 168-pin DIMM modules. The DRAM on
the SIMM modules can be either Fast Page mode or EDO
DRAM. DIMM modules can use these and can also use
the newer SDRAM (Synchronous DRAM). You can in-
stall a combined total 128MB of all memory types on the
PR5 mainboard.
Pentium-type CPUs are 64-bit CPUs. This has a direct
effect on the memory design. Since 72-pin SIMM sock-
ets are 32-bit, they have to be used in pairs to create a 64-
bit data path. This means that SIMM modules have to be
installed in pairs. The four SIMM sockets on the PR5 are
therefore divided into “ banks” of two sockets each, re-
sulting in two banks. Because DIMM sockets are 64-bit,
each DIMM functions as a bank, resulting in another two
banks for a total of four banks on the mainboard. The
SIMM banks are organized so that SIMM1/SIMM2 are
one bank, SIMM3/SIMM4 are another. The figure below
shows the socket numbering.
1 2 3 4 1 2
SIMMs
DI M M s
SIMM & DIMM memory sockets
Summary of Contents for PR5
Page 10: ...System Block Diagram ...