Populating Dimm Sockets - HP Compaq dc7700 DT Hardware Reference Manual

Populating DIMM Sockets

There are three DIMM sockets on the system board, with two sockets in memory Channel A and one
socket in memory Channel B. The sockets are labeled XMM1, XMM2, and XMM3. Sockets XMM1 and
XMM2 operate in memory Channel A; socket XMM3 operates in memory Channel B.
Figure 2-10
Item Description
1 DIMM socket XMM1, Channel A
2 DIMM socket XMM2, Channel A
3 DIMM socket XMM3, Channel B
The system will automatically operate in single channel mode, dual channel mode, or flex mode,
depending on how the DIMMs are installed.
●
The system will operate in single-channel mode if the DIMM sockets are populated in one channel
only.
●
The system will operate in a higher-performing dual channel mode if the total memory capacity of
the DIMMs in Channel A is equal to the total memory capacity of the DIMMs in Channel B. The
technology and device width can vary between the channels. For example, if Channel A is
populated with two 256MB DIMMs and Channel B is populated with one 512MB DIMM, the system
will operate in dual channel mode.
●
The system will operate in flex mode if the total memory capacity of the DIMMs in Channel A is not
equal to the total memory capacity of the DIMMs in Channel B. In flex mode, the channel populated
with the least amount of memory describes the total amount of memory assigned to dual channel
and the remainder is assigned to single channel. For optimal speed, the channels should be
balanced so that the largest amount of memory is spread between the two channels. For example,
if you are populating the sockets with two 1GB DIMMs and one 512MB DIMM, Channel A should
be populated with one 1GB DIMM and one 512MB DIMM and Channel B should be populated with
ENWW
DIMM Socket Locations
Socket Color
Black
White
White
Installing Additional Memory 17