Oracle^® Server X5-2 Service Manual

Populating DIMMs for Optimal System Performance

Optimal performance is achieved by populating the DIMMs so that the memory is symmetrical, or balanced. Symmetry is achieved by adhering to the following guidelines:

• In single-processor systems, populate DIMMs of the same size in multiples of four.

• In dual-processor systems. populate DIMMs of the same size in multiples of eight.

• Populate the DIMM sockets in the order described in the following sections.

The following sections provide an example of how to populate the DIMM sockets to achieve optimal system performance.

• Populating DIMMs in Single-Processor Systems for Optimal System Performance

• Populating DIMMs in Dual-Processor Systems for Optimal System Performance

Populating DIMMs in Single-Processor Systems for Optimal System Performance

In single-processor systems, install DIMMs only into DIMM sockets associated with processor 0 (P0). Starting with socket P0 D0. Fill the black sockets first, then the black sockets with white tabs, and then the white sockets, as shown in the following figure. Notice that the order of populating the black sockets is Ch C first, Ch A second, Ch D third, and Ch B last. Repeat the same population sequence for the black sockets with white tabs, and finally for the white sockets.

Figure 3  DIMM Population Order for Single-Processor Systems

The following table describes the proper order in which to populate DIMMs in a single-processor system using the numbered callouts in the above figure, the memory channel labels (Ch A through Ch D), and the DIMM socket labels (D0 through D11).

Table 12  DIMM Population Order for Single-Processor Systems

Population Order DIMMs Sockets for Processor 0 (P0) Memory Channels Fill the black sockets first First D0 Ch C Second D11 Ch A Third D3 Ch D Fourth D8 Ch B Then fill the black sockets with white tabs Fifth D1 Ch C Sixth D10 Ch A Seventh D4 Ch D Eighth D7 Ch B Then fill the white sockets Ninth D2 Ch C Tenth D9 Ch A Eleventh D5 Ch D Twelfth D6 Ch B

Populating DIMMs in Dual-Processor Systems for Optimal System Performance

In dual-processor systems, populate DIMMs into DIMM sockets starting with processor 0 (P0) D0, then, alternating between sockets associated with processor 0 (P0) and matching sockets for processor 1 (P1). Fill the black sockets first, then the black sockets with white tabs, and then the white sockets, as shown in the following figure. Notice that the order of populating the black DIMM sockets is Ch C first, Ch A second, Ch D third, and Ch B last. Repeat the same population sequence for the black sockets with white tabs, and finally, for the white sockets.

Figure 4  DIMM Population Order for Dual-Processor Systems

The following table describes the proper order in which to install DIMMs in a dual-processor system using the numbered callouts in the above figure, the memory channels labels (Ch A through Ch D), and the DIMM socket labels (D0 through D11).

Table 13  DIMM Population Order for Dual-Processor Systems

Population Order DIMM Sockets for Processor 0 (P0) DIMM Sockets for Processor 1 (P1) Memory Channels Fill the black sockets first Alternate between processor 0... ...and processor 1 First Fill D0 first Then fill D0 Ch C Second Fill D11 first Then fill D11 Ch A Third Fill D3 first Then fill D3 Ch D Fourth Fill D8 first Then fill D8 Ch B Fill the black sockets with white tabs Alternate between processor 0... ...and processor 1 Fifth Fill D1 first Then fill D1 Ch C Sixth Fill D10 first Then fill D10 Ch A Seventh Fill D4 first Then fill D4 Ch D Eighth Fill D7 first Then fill D7 Ch B Fill the white sockets last Alternate between processor 0... ...and processor 1 Ninth Fill D2 first Then fill D2 Ch C Tenth Fill D9 first Then fill D9 Ch A Eleventh Fill D5 first Then fill D5 Ch D Twelfth Fill D6 first Then fill D6 Ch B