User Manual

Memory bus operating frequency can be 1600 MT/s, 1333 MT/s, 1066 MT/s, or 800 MT/s depending on:

• DIMM type (UDIMM, RDIMM, or LRDIMM)

• DIMM configuration (number of ranks)

• maximum frequency of the DIMMs

• number of DIMMs populated per channel

• DIMM operating voltage

• system profile selected (for example, Performance Optimized, Custom, or Dense Configuration Optimized)

• maximum supported DIMM frequency of the processors

The system contains 24 memory sockets split into two sets of 12 sockets, one set per processor. Each 12-socket set is

organized into four channels. In each channel, the release levers of the first socket are marked white, the second socket

black, and the third socket green.

NOTE: DIMMs in sockets A1 to A12 are assigned to processor 1 and DIMMs in sockets B1 to B12 are assigned to

processor 2.

The following table shows the memory populations and operating frequencies for the supported configurations.

DIMM Type DIMMs Populated/

Channel

Operating Frequency (in MT/s) Maximum DIMM Rank/

Channel

1.5 V 1.35 V

UDIMM ECC 1 1333, 1066, and 800 1333, 1066, and 800 Dual rank

2 1333, 1066, and 800 1333, 1066, and 800 Dual rank

RDIMM 1

1600, 1333, 1066, and 800

1333, 1066, and 800

1066 and 800

Dual rank

Quad rank

1600, 1333, 1066, and 800

1066 and 800

1333, 1066, and 800

1066 and 800

Dual rank

Quad rank

3 1333, 1066, and 800 1066 and 800 Dual rank

LRDIMM 1 1333 and 1066 1333 and 1066 Quad rank

2 1333 and 1066 1333 and 1066 Quad rank

3 1066 1066 Quad rank