Product guide

A cost-optimized storage-rich alternative to traditional enterprise 2U dual-socket servers
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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, 8GB, and 16GB 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
Frequency
DIMMs per
Channel
Max. Memory
Capacity
5600 Series 5500 Series
1333MHz
1
(6 DIMMs)
96GB RDIMM
X5650, L5640,
E5645 and
above
N/A
1333MHz
2
5
(12 DIMMs)
192GB RDIMM
X5650, L5640,
E5645 and
above
N/A
1066MHz
2
(12 DIMMs)
192GB RDIMM All N/A
800MHz
2
(12 DIMMs)
192GB RDIMM N/A E5506, E5507
800MHz-
1333MHz
(Mirroring)
2
(8 DIMMs)
128GB RDIMM All All
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.
VMware ESXi includes all the performance, scalability and compatibility features of ESX, including
full VMFS support across FC SAN, iSCSI SAN, and NAS, and 4-way VSMP. Because it runs from
flash memory, it’s extremely fast and ideal for diskless configurations. It also offers enhanced
security, because it runs without an operating system-based console and is updated/patched much
like firmware. Licensing works the same as for “standard” ESX.
Disk Controllers
The x3620 M3 simple-swap models include firmware RAID-0/1 (in other words, without hardware
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2 DIMMs per channel at 1333MHz is supported only with 1.5V DIMMs or 1.35V DIMMs running at 1.5V.