Cpu/Memory; Introduction To Ddr Sdram - MSI MEGA651 PC User Manual

2.2 CPU/memory

The MEGA651 supports Intel
package. The mainboard uses a CPU socket called PGA478 for easy CPU
installation. When you are installing the CPU, make sure the CPU has a heat sink
and a cooling fan attached on the top to prevent overheating.
Overheating
Overheating will seriously damage the CPU and system,
always make sure the cooling fan can work properly to
protect the CPU from overheating.
The mainboard provides 2 slots for 184-pin DDR SDRAM DIMM (Double
In-Line Memory Module) modules and supports the memory size up to 2GB. You
can install PC2700/DDR333 or PC2100/DDR266 modules into the DDR DIMM
slots (CN28/26).

Introduction to DDR SDRAM

DDR (Double Data Rate) SDRAM is
similar to conventional SDRAM, but
doubles the rate by transferring data twice
per cycle. It uses 2.5 volts as opposed to 3.
3 volts used in SDR SDRAM, and requires
184-pin DIMM modules rather than 168-
pin DIMM modules used by SDR SDRAM.
High memory bandwidth makes DDR an
ideal solution for high performance PC,
workstations and servers.
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Pentium 4 processors in the 478-pin
Using PC Function
2-3