3.Align the other end of the retention bracket (near the retention bracket lock) to the retention module base. A clicking sound denotes that the retention bracket is in place.

Make sure that the fan and heatsink assembly perfectly fits the retention mechanism module base, otherwise you cannot snap the retention bracket in place.

4.Push down the retention bracket lock on the retention mechanism to secure the heatsink and fan to the module base.

5.When the fan and heatsink assembly is in place, connect the CPU fan cable to the connector on the motherboard labeled CPU_FAN.

Do not forget to connect the CPU fan connector! Hardware monitoring errors can occur if you fail to plug this connector.

1.7System memory

1.7.1Overview

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:

DIMM_B2

DIMM_A2

DIMM_B1

DIMM_A1

M3N78-CM

112 Pins 128 Pins

M3N78-CM 240-pin DDR2 DIMM Sockets

Channel

Socket

Channel A

DIMM_A1 and DIMM_A2

Channel B

DIMM_B1 and DIMM_B2

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ASUS M3N78-CM