Dell T620 owner manual General Memory Module Installation Guidelines, Dimm Type

	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	1333, 1066, and 800	1066 and 800	Dual rank
	2	1333, 1066, and 800	1066 and 800	Dual rank
RDIMM	1	1600, 1333, 1066, and	1333, 1066, and 800	Dual rank
		800
		1066 and 800	800	Quad rank
	2	1600, 1333, 1066, and	1333, 1066, and 800	Dual rank
		800
		800	800	Quad rank
	3	1066 and 800	Not Applicable	Dual rank
LRDIMM	1	1333 and 1066	1333 and 1066	Quad rank
	2	1333 and 1066	1333 and 1066	Quad rank
	3	1066	1066	Quad 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.

•Up to two quad-rank RDIMMs and up to three dual- or single-rank RDIMMs can be populated per channel. When a quad-rank RDIMM is populated in the first slot with white release levers, the third DIMM slot in the channel with green release levers cannot be populated.

•Up to three LRDIMMs can be populated regardless of rank count.

•Populate DIMM sockets only if a processor is installed. For single-processor systems, sockets A1 to A12 are available. For dual-processor systems, sockets A1 to A12 and sockets B1 to B12 are available.

•Populate all sockets with white release tabs first, then black, and then green.

•Do not populate the third DIMM socket in a channel with green release tabs, if a quad-rank RDIMM is populated in the first socket with white release tabs.

•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, if you want to mix quad-rank and dual-rank DIMMs, populate quad- rank DIMMs in the sockets with white release tabs and dual-rank DIMMs in the sockets with black release tabs.

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