Compaq dc5850 Service Reference Guide: HP Compaq dc5850 Business PC - Page 132

Populating DIMM Sockets There are four DIMM sockets on the system board, with two sockets per channel. The sockets are labeled XMM1, XMM2, XMM3, and XMM4. Sockets XMM1 and XMM3 operate in memory channel A. Sockets XMM2 and XMM4 operate in memory channel B. Item 1 2 3 4 Description DIMM socket XMM1, Channel A DIMM socket XMM2, Channel B DIMM socket XMM3, Channel A (populate second) DIMM socket XMM4, Channel B (populate first) Socket Color White White Black Black The system will automatically operate in single channel mode or dual channel mode, depending on how the DIMMs are installed. ● The system will operate in a higher-performing dual channel mode if like-sized DIMMs of equal capacity are populated in one or both pairs of sockets. For example, if the Channel A far socket and Channel B far socket (the two black sockets) both have 1024-MB DIMMs installed, the system will operate in dual channel mode. If this system had two additional DIMMs added into the white sockets, they could be a pair of 512-MB or 1024-MB DIMMs and the system would still operate in dual channel mode. For purposes of "like sizes," a single-sided 512-MB DIMM and a double-sided 512-MB DIMM would not be the same size because they have different numbers of memory chips on them. ● The system will operate in single channel mode if the DIMMs are populated in any other supported configuration. Supported configurations consist of any combination of one, two, three, or four DIMMs as long as socket XMM4 is populated before socket XMM2 in Channel B, and socket XMM3 is populated before socket XMM1 in Channel A. 120 Chapter 8 Removal and Replacement Procedures Small Form Factor (SFF) Chassis