Asus P4S8X P4S8X User Manual - Page 29

2.5 System memory 2.5.1 Overview The motherboard comes with three Double Data Rate (DDR) Dual Inline Memory Module (DIMM) sockets. These sockets support up to 3GB system memory using 184-pin unbuffered non-ECC PC2700/2100/1600 DIMMs. P4S8X ® P4S8X 184-Pin DDR DIMM Sockets 104 Pins 80 Pins A DDR DIMM is keyed with a notch so that it fits in only one direction. DO NOT force a DIMM into a socket to avoid damaging the DIMM. The DDR SDRAM technology evolved from the mainstream PC66, PC100, PC133 memory known as Single Data Rate (SDR) SDRAM. DDR memory however, has the ability to perform two data operations in one clock cycle, thus providing twice the throughput of SDR memory. DDR Data Transfer Rate 2.7 GB/s 2.1 GB/s 1.6 GB/s DDR Base Frequency 166MHz 133MHz 100MHz A DDR DIMM has the same physical dimensions as an SDR DIMM, but it has a 184-pin footprint compared to the 168-pin of the SDR DIMM. Also, a DDR DIMM is single notched while an SDR DIMM is double notched. Therefore, a DDR DIMM is not backward compatible with SDR, and should be installed only in a socket specially designed for DDR DIMMs. ASUS P4S8X motherboard user guide 17