Asus P55SP4 - Manual (Page 25)

P/I-P55SP4 User's Manual
Upgrading System Memory
This section explains how to install system memory. There are
instructions on how to configure and install memory and an expla­
nation of the technical specifications required.
System DRAM is the main source of data for the CPU. Data re­
mains stored in DRAM as long as the system is turned on, and is lost
when you turn it off. The Level 2 cache memory is Static RAM
(SRAM), which is faster than DRAM memory. When the CPU looks
for data, it first searches the cache. If the information is not there, the
search continues in the DRAM. With this design, the CPU looks in
the fastest source of data first, which lets it operate as fast as possible.
The DRAM subsystem uses memory chips permanently mounted
on small circuit boards to form ''SIMMs" (Single In-line Memory
Modules). The memory chips have a speed rating that is measured
in nanoseconds (ns). This mainboard requires either Fast Page Mode
(FPM) DRAM or Extended Data Output (EDO) DRAM with a speed
of at least 70ns.
This mainboard can use 72-pin SIMMs in four sizes from 1MB up
to 128MB (megabytes). Depending on the combination of modules
you use, you can install between 2MB and512MB. The 32-bit mod­
ules used for this board come with memory chips on either one or
both sides of the module.
IMPORTANT: Do not use SIMM modules with more than 24 chips
per module with this mainboard. Modules with more than 24 chips
exceed the design specifications of the memory subsystem and will
cause unreliable operation. DO NOT use 32 or 36-chip modules with
this mainboard.
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