channel 2: memory sockets C3, C7, and C11channel 3: memory sockets C4, C8, and C12Processor 4 channel 0: memory sockets D1, D5, and D9channel 1: memory sockets D2, D6, and D10channel 2: memory sockets D3, D7, and D11channel 3: memory sockets D4, D8, and D12The following table shows the memory populations and operating frequencies for the supported configurations.DIMM Type DIMMs Populated/Channel Operating Frequency (in MT/s) Maximum DIMM Rank/Channel1.5 V 1.35 VRDIMM 1 1600, 1333, 1066, and8001333, 1066, and 800 Dual rank1333, 1066, and 800 1066 and 800 Quad rank2 1600, 1333, 1066, and8001333, 1066, and 800 Dual rank1066 and 800 1066 and 800 Quad rank3 1333, 1066, and 800 1066 and 800 Dual rankLRDIMM 1 1333 and 1066 1333 and 1066 Quad rank2 1333 and 1066 1333 and 1066 Quad rank3 1066 1066 Quad rankGeneral Memory Module Installation GuidelinesThis system supports Flexible Memory Configuration, enabling the system to be configured and run in any valid chipsetarchitectural configuration. The following are the recommended guidelines for best performance:• RDIMMs and LRDIMMs must not be mixed.• x4 and x8 DRAM based DIMMs can be mixed. For more information, see Mode-Specific Guidelines.• Up to two quad-rank RDIMMs and up to three dual- or single-rank RDIMMs can be populated per channel.• Up to three LRDIMMs can be populated regardless of rank count.• Populate DIMM sockets only if a processor is installed. For dual-processor systems, sockets A1 to A12 and B1 toB12 are available. For four-processor systems, sockets A1 to A12, B1 to B12, C1 to C12, and D1 to D12 areavailable.• Populate the sockets by highest rank count in the following order - first in sockets with white release levers,then black, and then green. For example, to mix quad-rank and dual-rank DIMMs, populate quad-rank DIMMs inthe sockets with white release tabs and dual-rank DIMMs in the sockets with black release tabs.• In a dual- or four-processor configuration, the memory configuration for each processor must be identical. Forexample, if you populate socket A1 for processor 1, then you must populate socket B1 for processor 2, and soon.• Memory modules of different sizes can be mixed provided that other memory population rules are followed (forexample, 2 GB and 4 GB memory modules can be mixed).• Populate four DIMMs per processor (one DIMM per channel) at a time to maximize performance.• If memory modules with different speeds are installed, they operate at the speed of the slowest installedmemory module(s) or slower depending on system DIMM configuration.53