Asus P2-99B P2-99B User Manual - Page 19

III. HARDWARE SETUP 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. Lock P2-99B R 20 Pins 60 Pins 88 Pins P2-99B 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) III. H/W SETUP System Memory DRAM Key Position RFU Unbuffered Buffered Voltage Key Position 5.0V Reserved 3.3V 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. ASUS P2-99B User's Manual 19