The server memory control subsystem selects a proper rank within the DIMM when data is
written to or read from the DIMM.
Dual- and quad-rank DIMMs provide the greatest capacity with the existing memory
technology. For example, if the current DRAM technology supports 8 GB single-rank
DIMMs, a dual-rank DIMM can offer a capacity of 16 GB, and a quad-rank DIMM can offer
a capacity of 32 GB.
LRDIMMs are labeled as quad-rank DIMMs. There are four ranks of DRAM on the DIMM,
but the LRDIMM buffer creates an abstraction that allows the DIMM to appear as a logical
dual-rank DIMM to the system. The LRDIMM buffer also isolates the electrical loading of
the DRAM from the system to allow for faster operation. These two changes provide a higher
memory operating speed compared with quad-rank RDIMMs.
5.13.4 DIMM Identification
To determine DIMM characteristics, see the label attached to the DIMM and refer to the
following figure and table.
Figure 5-52
DIMM identification
No.
Description
Definition
1
Capacity
l
8 GB
l
16 GB
l
32 GB
l
64 GB
2
Rank
l
1R: single-rank
l
2R: dual-rank
l
4R: quad-rank
3
Data width on DRAM
l
x4: 4-bit
l
x8: 8-bit
4
Memory generation
PC4: DDR4
2288H V5 Server
User Guide
5 Optional Part Installation
Issue 04 (2018-09-04)
Copyright © Huawei Technologies Co., Ltd.
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