In 2012, memory content on high-volume Intel and AMD processor based servers is exploding. Intel E5-2600 and AMD Opteron 6100/6200 processor based 2-way servers can generally support up to 24 memory sockets. New E5-4600 processer based servers have up to 48 memory sockets and the E7 servers up to 64 memory sockets. This memory expansion provides new and unmatched flexibility for server architects to configure servers with high memory content for demanding applications such as Performance Clouds, Virtualization and VDI, Big Data, In-Memory Databases such as SAP HANA, HPC and other memory-hungry applications that can take advantage of powerful multicore processors.
While Kingston’s 16GB Registered DIMMs are now becoming more common on higher-end servers, there is a new option to use Kingston 32GB memory modules that will be available in 2012 in two varieties – Registered DIMMs (RDIMMs), similar to modules that have been used in servers in the past, and Load Reduced DIMMs (LRDIMMs), which are newly supported technology on the Intel E5 and select AMD Opteron 6200 processor based platforms.
For more information about LRDIMMs, please consult our white papers.
Whether you need to use a 32GB RDIMM or LRDIMM will depend upon your requirements – just note that in a single server, RDIMMs and LRDIMMs cannot be mixed. You must configure each server exclusively with LRDIMMs or RDIMMs.
First of all, both the 32GB RDIMM and the 32GB LRDIMM are physically Quad Rank modules – the difference being that the LRDIMM technology uses on-module buffers to make the module appear to the memory controller as a Dual Rank module. This means that, on Intel E5 processor-based platforms, 32GB LRDIMMs can be used in all the available memory sockets whereas 32GB Quad Rank RDIMMs are limited to a maximum 2 DIMMs per Channel (2DPC) configurations as illustrated in the table below (which also shows the maximum memory speed supported in the different configurations):
(No Mixing in a Server)
||1 DIMM per Channel
|2 DIMMs per Channel
|3 DIMMs per Channel
|32 GB RDIMM
|32GB Load Reduced DIMM (LRDIMM)
Table 1: Maximum memory speeds per memory configuration. A platform’s effective memory speed (also called Data Rate) is a factor of the processor’s rated memory speed, the memory modules’ Ranks and speed, and the platform’s configuration in 1DPC, 2DPC and 3DPC.
As an example, let’s consider a 24 memory socket Intel E5-2600 processor based 2-way server. This server can be configured as follows for maximum memory capacity:
- Twenty-four 32GB LRDIMMs for a maximum capacity of 768GB of memory, running at 1066MHz at 1.5V (this is a 3DPC configuration).
- Sixteen 32GB Quad Rank RDIMMs for a maximum capacity of 512GB of memory, running at 800MHz at 1.5V (this is a 2DPC configuration).
Note that HP’s ProLiant Gen8 servers do not officially support the use of Quad Rank modules, so the only option would be to use 32GB LRDIMMs.
On the Xeon E5-4600 processor based platforms with up to 48 memory sockets per server, the options will be:
- Forty-eight 32GB LRDIMMs for a maximum capacity of 1536GB or 1.5TB of memory, running at 1066MHz at 1.5V (this is a 3DPC configuration).
- Thirty-two 32GB QR RDIMMs for a maximum capacity of1024GB or 1TB of memory, running at 800MHz at 1.5V (this is a 3DPC configuration).
On higher end 4-way and greater processor servers, such as the Intel E7 processor based servers, memory content will be even greater with the 32GB Quad Rank RDIMMs (the E7 servers do not support the LRDIMM technology). On a 64-socket 4-way server, memory content using the 32GB RDIMM could top at 2TB.
AMD Opteron 6100 or 6200 processor based 2-way platforms support Quad Rank RDIMMs as follows:
- Up to sixteen 32GB Quad Rank modules for servers with sixteen memory sockets for a maximum capacity of 512GB of memory, running at 1066MHz and 1.5V (this is a 2DPC configuration).
- Up to eight 32GB Quad Rank modules for servers with twenty-four memory sockets. In this case, the remaining sixteen sockets can be populated with 16GB Dual Rank modules for a maximum capacity of 512GB of memory, running at 800MHz (this is a mixed 3DPC configuration).
32GB modules, whether Registered DIMMs or Load Reduced DIMMs, will allow servers to reach very high memory capacities that will enable the added performance capabilities of new multicore processors.