MSI MS-6566 - Manual (Page 22)

Hardware Setup
2-5
The mainboard provides 2 slots for 184-pin, 2.5V unbuffered DDR DIMM
with 4 memory banks. You can install PC1600/PC2100 DDR SDRAM modules
on the DDR DIMM slots (DDR 1~2). To operate properly, at least one DIMM
module must be installed.
Memory
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 op-
posed 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 band-
width makes DDR an ideal solution for high performance PC, workstations and
servers.
DDR DIMM Slots
(DDR 1~2)