Dell 840 General Memory Module Installation Guidelines, Installing Memory Modules, MB None

Memory

You can upgrade your system memory to a maximum of 8 GB by installing combinations of 512-MB, 1-GB, and 2-GB unbuffered ECC DDRII SDRAM 533- or 667-MHz memory modules. The system memory is located on the system board adjacent to the power supply connectors. See "System Board Connectors" on page 118. The memory module sockets are arranged in two banks on two channels (A and B). The memory module banks are identified as follows:

•Bank 1: DIMM1_A and DIMM1_B

•Bank 2: DIMM2_A and DIMM2_B

General Memory Module Installation Guidelines

•If only one memory module is installed, it must be installed in socket DIMM1_A.

•If two or more memory modules are installed, they must be installed in pairs of matched memory size, speed, and technology.

Table 3-2 shows examples of different memory configurations.

Table 3-2. Sample Memory Configurations

Total Memory	DIMM1_A	DIMM2_A DIMM1_B		DIMM2_B
512 MB	512 MB	None	None	None
1 GB	512 MB	None	512 MB	None
1 GB	1 GB	None	None	None
2 GB	512 MB	512 MB	512 MB	512 MB
2 GB	1 GB	None	1 GB	None
3 GB	1 GB	512 MB	1 GB	512 MB
4 GB	1 GB	1 GB	1 GB	1 GB
4 GB	2 GB	None	2 GB	None
5 GB	2 GB	512 MB	2 GB	512 MB
6 GB	2 GB	1 GB	2 GB	1 GB
8 GB	2 GB	2 GB	2 GB	2 GB

Installing Memory Modules

CAUTION: Only trained service technicians are authorized to remove the system cover and access any of the components inside the system. Before performing any procedure, see your Product Information Guide for complete information about safety precautions, working inside the computer, and protecting against electrostatic discharge.

1Turn off the system, including any attached peripherals, and disconnect the system from the electrical outlet.

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Installing System Components