Asus M3A78-EM - Manual (Page 28)

1-16 Chapter 1: Product introduction
1.7 System memory
1.7.1. Overview
The motherboard comes with four Double Data Rate 2 (DDR2) Dual Inline Memory
Modules (DIMM) sockets.
A DDR2 module has the same physical dimensions as a DDR DIMM but has a
240-pin footprint compared to the 184-pin DDR DIMM. DDR2 DIMMs are notched
differently to prevent installation on a DDR DIMM socket.
The figure illustrates the location of the DDR2 DIMM sockets:
Channel Sockets
Channel 1 DIMM_A1 and DIMM_A2
Channel 2 DIMM_B1 and DIMM_B2
1.7.2 Memory configurations
You may install 256 MB, 512 MB, 1 GB, and 2 GB unbuffered ECC/non-ECC
DDR2 DIMMs into the DIMM sockets.
Recommended memory configurations
Sockets
Mode DIMM_A1 DIMM_B1 DIMM_A2 DIMM_B2
Single-Channel
– Populated – –
Populated – – –
Dual-channel.(1) Populated Populated – –
Dual-channel.(2) Populated Populated Populated Populated
M3A78-EM 240-pin DDR2 DIMM Sockets
R
M3A78-EM
DIMM_B1 DIMM_A2 DIMM_B2 DIMM_A1
128 Pins
11
2 Pins