Dell PowerEdge R820 Technical Manual

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Contents

18 PowerEdge R820 Technical GuideThe R820 supports the DIMMs listed in Table 8. For the latest information on supported memory,visit Dell.com/PowerEdge.Table 8. DIMMs supportedCapacity(GB)Speed(MT/s) Type Ranks perDIMMDatawidth SDDC support Voltage4 1600 RDIMM 1 x8 Advanced ECC 1.358 1600 RDIMM 1 x4 All modes 1.3516 1600 RDIMM 2 x4 All modes 1.3532 1333 RDIMM 4 x4 All modes 1.3532 1333 LRDIMM 4 x4 All modes 1.3532 1600 LRDIMM 4 x4 All modes 1.35Memory configurationsThe R820 server supports flexible memory configurations ranging from capacities of 4GB to1.5TB. The R820 supports up to 12 DIMMs per processor (up to 48 DIMMs in a four-processorconfiguration). The R820 has four memory channels per processor, with each channel supportingup to three DIMMs.The R820 supports a flexible memory configuration according to these basic rules: Speed: If DIMMs of different speeds are mixed, all channels across all processors operate at theslowest DIMM’s common frequency. DIMM type: Only one type of DIMM is allowed per system. UDIMM, RDIMM and LRDIMM cannotbe mixed.The following additional memory population guidelines apply to the R820: Up to two quad-rank (QR) DIMMs and up to three dual-rank (DR) or single-rank (SR) DIMMs maybe populated per channel. Although an LRDIMM is physically a QR DIMM, logic on the LRDIMMcan make it appear as a DR DIMM to the system, allowing up to three LDRIMMs per channel. DIMMs must be installed in each channel, starting with the DIMM farthest from the processor. DIMMs should be installed with largest rank count to smallest. For example, if DR DIMMS aremixed with SR DIMMs, DR DIMMS should be placed in the lowest DIMM slots, followed by the SRDIMMs.For more information on memory configuration, see theDell PowerEdge R820 Owner’s Manual onDell.com/Support/Manuals.Memory speedThe R820 supports memory speeds of up to 1600MT/s, depending on the DIMM types installed andthe configuration. All memory on all processors and channels run at the same speed and voltage. Bydefault, the systems run at the highest speed for the channel with the lowest DIMM voltage andspeed. The operating speed of the memory is also determined by the maximum speed supported bythe processor, the speed settings in the BIOS and the operating voltage of the system.Visit the PowerEdge memory page on Dell.com for the latest memory configuration andperformance details for the R820 based on the population of the number and type of DIMMs permemory channel.