Hp Smartmemory; Memory Subsystem Architecture; Single-, Dual-, And Quad-Rank Dimms - HP ProLiant XL230a Gen9 User Manual

Depending on the processor model, the number of DIMMs installed, and whether LRDIMMs or RDIMMs are
installed, the memory clock speed can be reduced to 1600 MT/s.
Populated DIMM speed (MT/s)
DIMM type
RDIMM
RDIMM
LRDIMM

HP SmartMemory

HP SmartMemory authenticates and unlocks certain features available only on HP Qualified memory and
verifies whether installed memory has passed HP qualification and test processes. Qualified memory is
performance-tuned for HP ProLiant and BladeSystem servers and provides future enhanced support through
HP Active Health and manageability software.

Memory subsystem architecture

The memory subsystem in this server is divided into channels. Each processor supports four channels, and
each channel supports two DIMM slots, as shown in the following table.
Channel
1
2
3
4
For the location of the slot numbers, see "DIMM slot locations (on page 9)."
This multi-channel architecture provides enhanced performance in Advanced ECC mode.
DIMM slots in this server are identified by number and by letter. Letters identify the population order. Slot
numbers indicate the DIMM slot ID for spare replacement.

Single-, dual-, and quad-rank DIMMs

To understand and configure memory protection modes properly, an understanding of single-, dual-, and
quad-rank DIMMs is helpful. Some DIMM configuration requirements are based on these classifications.
A single-rank DIMM has one set of memory chips that is accessed while writing to or reading from the
memory. A dual-rank DIMM is similar to having two single-rank DIMMs on the same module, with only one
rank accessible at a time. A quad-rank DIMM is, effectively, two dual-rank DIMMs on the same module. Only
one rank is accessible at a time. The server memory control subsystem selects the proper rank within the
DIMM when writing to or reading from the DIMM.
DIMM rank
Single-rank (8 GB)
Dual-rank (16 GB)
Quad-rank (32 GB)
Processor 1 slot Processor 1 slot
number
A 8
E 7
B 6
F 5
C 1
G 2
D 3
H 4
1 DIMM per channel
2133
2133
2133
Processor 2 slot
A
E
B
F
C
G
D
H
2 DIMMs per channel
2133
2133
2133
Processor 2 slot
number
1
2
3
4
8
7
6
5
Hardware options installation 31