Memory Subsystem; Registered Dimm; Memory Placement Rules - IBM Power 750 Technical Overview And Introduction

considerations should be taken into account as when deploying workloads that span multiple
system enclosures on a Power 770 or Power 780 server to achieve optimum performance.
For more information, see the "Architecture of the IBM POWER7+ Technology-based
IBM Power 750 and IBM Power 760" technote:
http://www.redbooks.ibm.com/Redbooks.nsf/RedbookAbstracts/tips0972.html?Open

2.3 Memory subsystem

The Power 750 and Power 760 servers are a four-socket systems supporting four POWER7+
DCM processor modules. Each DCM processor module activates two memory riser cards
with eight DDR3 DIMM slots for each card. The server supports a maximum of 64 DDR3
DIMM slots using all 16 riser cards and all DCM modules.
The DIMM cards are 30 mm high, industry standard DDR3 Registered DIMMs. Memory
features (two memory DIMMs per feature) supported in the Power 750 are 4 GB, 8 GB, and
16 GB. The Power 760 additionally supports the 32 GB DIMMs. All DIMMs run at a speeds of
1066 MHz. The maximum memory supported using all DIMM slots is 1 TB for the Power 750
and 2 TB for the Power 760.

2.3.1 Registered DIMM

Industry standard DDR3 Registered DIMM (RDIMM) technology is used to increase reliability,
speed, and density of memory subsystems by putting a register between the DIMM modules
and the memory controller. This register is also referred to as a buffer.

2.3.2 Memory placement rules

The following memory options are orderable for the Power 750 system:
8 GB (2 x 4 GB) Memory DIMMs, 1066 MHz (FC EM08)
16 GB (2 x 8 GB) Memory DIMMs, 1066 MHz (FC EM4B, CCIN 31FA)
32 GB (2 x 16 GB) Memory DIMMs, 1066 MHz (FC EM4C)
The following memory options are orderable for the Power 760 system:
8 GB (2 x 4 GB) Memory DIMMs, 1066 MHz (FC EM08)
16 GB (2 x 8 GB) Memory DIMMs, 1066 MHz (FC EM4B, CCIN 31FA)
32 GB (2 x 16 GB) Memory DIMMs, 1066 MHz (FC EM4C)
64 GB (2 x 32 GB) Memory DIMMs, 1066 MHz (FC EM4D)
The minimum DDR3 memory capacity for the Power 750 and Power 760 systems is 32 GB of
installed memory for systems using one or two DCMs, 48 GB for three DCMs and 64 GB for
four DCMs. Although a single DCM system with two memory riser cards using the smallest
4 GB DIMMs can have a minimum of 16 GB (2 riser cards x 2 DIMMs with 4 GB = 16 GB), the
minimum memory is 32 GB. See Table 2-3.
Table 2-3 Maximum memory of the Power 750 and Power 760 system
Number of DCMs
One DCM
Two DCMs
54
IBM Power 750 and 760 Technical Overview and Introduction
Power 750
256 GB
512 GB
Power 760
512 GB
1024 GB