IBM System x3620 M3 Product Manual

Also see for System x3620 M3 7376: Installation and user guide Installation and user guide Manual

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A cost-optimized storage-rich alternative to traditional enterprise 2U dual-socket serversPlease see the Legal Information section for important notices and information. 6The 5500 and 5600 Series processors support single-, dual-, and quad-rank memory. A memoryrank 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 rankIt is important to ensure that DIMMs with the appropriate number of ranks are populated in eachchannel 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. Forinstance, a system populated with six 2GB dual-rank DIMMs outperforms a system populatedwith six 2GB single-rank DIMMs by 7% for SPECjbb2005. Dual-rank DIMMs are also better thanquad-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, mixingone 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 relativememory bandwidth decreases as the number of channels populated decreases. This is becausethe 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 onthe remaining channels, causing them to become a bottleneck. If 1.5V and 1.35V DIMMs aremixed, all DIMMs will run at 1.5V.In addition to Chipkill error correction, the x3620 M3 offers an additional level of IBM ActiveMemory protection: memory mirroring.Memory mirroring works much like disk mirroring. The total memory is divided into threechannels: a primary channel, a backup channel, and an unused channel. Data is writtenconcurrently to both the primary and backup channels. If a DIMM fails in one of the DIMMs in theprimary channel, it is instantly disabled and the mirrored memory in the backup channel becomesactive (primary) until the failing DIMM is replaced. One-third of total memory is available for useat any one time with mirroring enabled. (Note: Due to the double writes to memory, performanceis affected.) Because the third channel is disabled with mirroring active, there is no point inpopulating 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 beinstalled 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:MemoryFrequencyDIMMs perChannelMax. MemoryCapacity 5600 Series 5500 Series1333MHz 1(6 DIMMs) 48GB RDIMM X5650, L5640and above N/A1333MHz 26(12 DIMMs) 96GB RDIMM X5650, L5640and above N/A1066MHz 2(12 DIMMs) 96GB RDIMM E5620, L5630and above N/A800MHz 2(12 DIMMs) 96GB RDIMM N/A E5506, E5507800MHz-1333MHz2(8 DIMMs) 64GB RDIMM All AllIntegrated VirtualizationAll models of the x3620 M3 support a USB 2.0 Flash Key installed preloaded with VMwareESXi 4.0 ESXi is an embedded version of VMware ESX 4.0, fully contained on the flash driveand requiring no disk space—not an “ESX Lite.” Rather than management through a ServiceConsole based on a Linux operating system, ESXi relies on aggregate management tools,including VirtualCenter, the Remote Command Line interface and the introduction of CIM forstandards-based and agentless hardware monitoring.6 2 DIMMs per channel at 1333MHz is supported only with 1.5V RDIMMs.