Single- And Dual-Rank Dimms; Dimm Identification - HP ProLiant DL160 Gen8 User Manual

Single- and dual-rank DIMMs

DIMM configuration requirements are based on these classifications:
•
Single-rank DIMM−One set of memory chips that is accessed while writing to or reading from the
memory.
•
Dual-rank DIMM−Two single-rank DIMMs on the same module, with only one rank accessible at a time.
The server memory control subsystem selects the proper rank within the DIMM when writing to or reading
from the DIMM.
Dual-rank DIMMs provide the greatest capacity with the existing memory technology. For example, if current
DRAM technology supports 2-GB single-rank DIMMs, a dual-rank DIMM would be 4-GB.

DIMM identification

To determine DIMM characteristics, use the label attached to the DIMM and the following illustration and
table.
Item Description
Size
1
Rank
2
Data width
3
Voltage rating
4
Memory speed
5
DIMM type
6
Definition
—
1R = Single-rank
2R = Dual-rank
4R = Quad-rank
x4 = 4-bit
x8 = 8-bit
L = Low voltage (1.35v)
U = Ultra low voltage (1.25v)
Blank or omitted = Standard
12800 = 1600-MT/s
10600 = 1333-MT/s
8500 = 1066-MT/s
R = RDIMM (registered)
E = UDIMM (unbuffered with ECC)
L = LRDIMM (load reduced)
Hardware options installation 37