Memory; Introduction To Ddr Sdram - MSI 661FM Series User Manual

The mainboard provides two 184-pin unbuffered DDR266/DDR333/
DDR400 DDR SDRAM, and supports the memory size up to 2GB without ECC.
To operate properly, at least one DIMM module must be installed.
(For the updated supporting memory modules, please visit http://www.msi.com.
tw/program/products/mainboard/mbd/pro_mbd_trp_list.php )

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.
MSI Reminds You...
For Micron MT46V32M8TG-5B DDR400 memory module,
please be sure to install 2 dimms to avoid the incompatibility
issue.

Memory

DDR DIMM Slots
(DDR 1~2)
Hardware Setup
2-7