IBM X3620 M3 specifications Integrated Virtualization

A cost-optimized storage-rich alternative to traditional enterprise 2U dual-socket servers

The 5500 and 5600 Series processors support single-, dual-, and quad-rank memory. A memory rank is simply a segment of memory that is addressed by a specific address bit.

•A typical memory DIMM description is 4GB 2Rx4 DIMM

•The 2R designator is the rank count for this particular DIMM (2R = dual-rank)

•The x4 designator is the data width of the rank

It is important to ensure that DIMMs with the appropriate number of ranks are populated in each channel for optimal performance. Whenever possible, use dual-rank DIMMs in the system. Dual- rank DIMMs offer better interleaving and hence better performance than single-rank DIMMs. For instance, a system populated with six 2GB dual-rank DIMMs outperforms a system populated with six 2GB single-rank DIMMs by 7% for SPECjbb2005. Dual-rank DIMMs are also better than quad-rank DIMMs because quad-rank DIMMs will cause the memory speed to be down- clocked.

Another important guideline is to populate equivalent ranks per channel. For instance, mixing one single-rank DIMM and one dual-rank DIMM in a channel should be avoided.

Notes: It is important to populate all three memory channels in each processor. The relative memory bandwidth decreases as the number of channels populated decreases. This is because the bandwidth of all the memory channels is utilized to support the capability of the processor. So, as the channels are decreased, the burden to support the requisite bandwidth is increased on the remaining channels, causing them to become a bottleneck. If 1.5V and 1.35V DIMMs are mixed, all DIMMs will run at 1.5V.

In addition to Chipkill error correction, the x3620 M3 offers an additional level of IBM Active

Memory protection: memory mirroring.

Memory mirroring works much like disk mirroring. The total memory is divided into three channels: a primary channel, a backup channel, and an unused channel. Data is written concurrently to both the primary and backup channels. If a DIMM fails in one of the DIMMs in the primary channel, it is instantly disabled and the mirrored memory in the backup channel becomes active (primary) until the failing DIMM is replaced. One-third of total memory is available for use at any one time with mirroring enabled. (Note: Due to the double writes to memory, performance is affected.) Because the third channel is disabled with mirroring active, there is no point in populating it with memory.

Mirroring is handled at the hardware level; no operating system support is required.

DDR3 memory is currently available in 1GB, 2GB, 4GB and 8GB RDIMMs. DIMMs can be installed individually (not in pairs). However, for performance reasons, in a 2-processor system, it’s best to install a DIMM per processor.

Maximum memory capacity and speed in 2-processor configurations include:

Memory	DIMMs per	Max. Memory	5600 Series	5500 Series
Frequency	Channel	Capacity
1333MHz	1	48GB RDIMM	X5650, L5640	N/A
	(6 DIMMs)		and above
1333MHz	26	96GB RDIMM	X5650, L5640	N/A
	(12 DIMMs)		and above
1066MHz	2	96GB RDIMM	E5620, L5630	N/A
	(12 DIMMs)		and above
800MHz	2	96GB RDIMM	N/A	E5506, E5507
	(12 DIMMs)
800MHz-	2	64GB RDIMM	All	All
1333MHz	(8 DIMMs)

Integrated Virtualization

All models of the x3620 M3 support a USB 2.0 Flash Key installed preloaded with VMware ESXi 4.0 ESXi is an embedded version of VMware ESX 4.0, fully contained on the flash drive and requiring no disk space—not an “ESX Lite.” Rather than management through a Service Console based on a Linux operating system, ESXi relies on aggregate management tools, including VirtualCenter, the Remote Command Line interface and the introduction of CIM for standards-based and agentless hardware monitoring.

62 DIMMs per channel at 1333MHz is supported only with 1.5V RDIMMs.

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