Dell R720 General Memory Module Installation Guidelines, Processor, DIMM Type, Maximum DIMM Rank

Processor 1	channel 0: slots A1, A5, and A9
	channel 1: slots A2, A6, and A10
	channel 2: slots A3, A7, and A11
	channel 3: slots A4, A8, and A12
Processor 2	channel 0: slots B1, B5, and B9
	channel 1: slots B2, B6, and B10
	channel 2: slots B3, B7, and B11
	channel 3: slots B4, B8, and B12

The following table shows the memory populations and operating frequencies for the supported configurations.

DIMM Type	DIMMs Populated/	Operating Frequency (in MT/s)		Maximum DIMM Rank/
	Channel			Channel
		1.5 V	1.35 V
UDIMM ECC	1	1600, 1333, 1066, and	1600, 1333, 1066 and 800	Dual rank
		800
	2	1600, 1333, 1066, and	1600, 1333, 1066 and 800	Dual rank
		800
RDIMM	1	1866, 1600, 1333, 1066,	1600, 1333, 1066, and 800	Dual rank
		and 800
		1333, 1066 and 800	1066 and 800	Quad rank
	2	1866, 1600, 1333, 1066,	1600, 1333, 1066, and 800	Dual rank
		and 800
		1066 and 800	1066 and 800	Quad rank
	3	1333, 1066 and 800	1066 and 800	Dual rank
LRDIMM	1	1866, 1600, 1333 and	1600, 1333 and 1066	Quad rank
		1066
		1600, 1333 and 1066	Not applicable	Octal rank
	2	1600, 1333 and 1066	1600, 1333 and 1066	Quad rank
		1600, 1333 and 1066	Not applicable	Octal rank
	3	1333 and 1066	1066	Quad rank
		1333 and 1066	Not applicable	Octal rank

General Memory Module Installation Guidelines

This system supports Flexible Memory Configuration, enabling the system to be configured and run in any valid chipset architectural configuration. The following are the recommended guidelines for best performance:

•UDIMMs, RDIMMs, and LRDIMMs must not be mixed.

•x4 and x8 DRAM based DIMMs can be mixed. For more information, see Mode-Specific Guidelines.

•A maximum of two UDIMMs can be populated in a channel.

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