Asus M4A89TD PRO/USB3 - Manual (Page 28)

2-10 Chapter 2: Hardware information
Chapter 2
2.4 System memory
2.4.1 Overview
The motherboard comes with four Double Data Rate 3 (DDR3) Dual Inline Memory Modules
(DIMM) sockets.
A DDR3 module has the same physical dimensions as a DDR2 DIMM but is notched
differently to prevent installation on a DDR2 DIMM socket. DDR3 modules are developed for
better performance with less power consumption.
The figure illustrates the location of the DDR3 DIMM sockets:
Recommended memory configurations
One DIMM:
When installing one memory module, we suggest that you install it on A1 slot.
Two DIMMs (dual-channel operation):
Four DIMMs (dual-channel operation):