III. INSTALLATION
DIMM Memory Installation Procedures:
Insert the module(s) as shown. Because the number of pins are different on either
side of the breaks, the module will only fit in the orientation as shown. DRAM
SIMM modules have the same pin contacts on both sides. SDRAM DIMMs have
different pin contacts on each side and therefore have a higher pin density.
88 Pins
60 Pins
20 Pins
Lock
P5A-B 168-Pin DIMM Memory Sockets
The DIMMs must be 3.3Volt unbuffered SDRAMs. To determine the DIMM type,
check the notches on the DIMMs (see figure below).
168-Pin DIMM Notch Key Definitions (3.3V)
Voltage Key Position
DRAM Key Position
Reserved
RFU
Unbuffered
5.0V
3.3V
Buffered
The notches on the DIMM will shift between left, center, or right to identify the type
and also to prevent the wrong type from being inserted into the DIMM slot on the
motherboard. You must tell your retailer the correct DIMM type before purchasing.
This motherboard supports four clock signals per DIMM.
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ASUS P5A-B User's Manual