DIMM identification
To determine DIMM characteristics, use the label attached to the DIMM and the following illustration
and table.
Definition
Description
Item
—
Size
1
1R = Single-rank2R = Dual-rank4R =
Quad-rank
Rank
2
x4 = 4-bitx8 = 8-bit
Data width
3
10600 = 1333-MHz8500 =
1066-MHz
Memory speed
4
R = RDIMM (registered)
DIMM type
5
For the latest supported memory information, see the QuickSpecs on the HP website (
).
DIMM installation guidelines
This server supports two memory cartridges per processor. Each memory cartridge can support up
to eight DIMMs. Eight memory cartridges provide a total of 128 DIMMs per system. When installing
DIMMs in the memory cartridge, observe the following minimum guidelines:
•
The minimum configuration is two DIMMs per cartridge. Running in Lockstep mode, such
DIMM pairs offer larger memory protection to provide increased memory fault resiliency.
•
DIMMs must be installed in quads with identical characteristics. When possible, for
configuration simplicity, HP recommends using DIMMs with identical part numbers throughout
the system.
•
DIMM quads must be populated in sequence by letter designation. Install DIMM quad (1A,
8A in both cartridges) first, followed by DIMM quad (3B, 6B in both cartridges), DIMM quad
(2C, 7C in both cartridges) and DIMM quad (4D, 5D in both cartridges).
•
To achieve maximum performance, balance DIMM quads by letter groupings across all memory
cartridges so that the (1A, 8A) pair is installed in all memory cartridges first, followed by the
B-pair, C-pair, and D-pair.
•
When installing mixed rank DIMMs in any cartridge, DIMMs with the highest number of ranks
must be installed in the white DIMM connector locations. This guarantees proper electrical
signaling on the DDR3 channel since DIMMs with higher rank counts present larger electrical
loading on the DDR3 channel and must be populated at the end point of the channel. For
more information, see the illustration below.
CAUTION:
Failure to follow these guidelines may result in the inability to recognize memory,
memory errors, or reduced memory performance.
NOTE:
To utilize more than 128GB per processor socket, 44-bit addressing mode must be
used (40-bit versus 44-bit addressing is configured in the RBSU). Not all supported operating
systems support 44-bit addressing mode; refer to the desired operating system documentation
to ensure 44-bit addressing is supported. In 40-bit mode, systems with 4 installed processors
are limited to a maximum of 512GB, and systems with 8 installed processors are limited to
a maximum of 1TB of addressable memory.
DIMMs
35
