Dell PowerEdge 1850 - Manual (Page 49)

System Memory
The six memory module sockets can accommodate from 256 MB to 16GB of registered ECC PC2-3200 (DDR 2 400) memory. The memory sockets are located on
the system board adjacent to the power supply bays. See
Figure 6 -1 .
You can upgrade the system memory by installing combinations of 256-, 512-MB, 1-GB, 2-GB, and 4-GB (when available) registered memory modules.
The memory module sockets are arranged in three banks on two channels (A and B). The memory module banks are identified as follows:
l Bank 1: DIMM1_A and DIMM1_B
l Bank 2: DIMM2_A and DIMM2_B
l Bank 3: DIMM3_A and DIMM3_B
General Memory Module Installation Guidelines
l If only one memory module is installed, it must be installed in socket DIMM1_A or DIMM1B.
l If two or more memory modules are installed, they must be installed in pairs of matched memory size, speed, and technology.
l The system supports both single-ranked and dual-ranked memory modules.
l If you install both single-ranked and dual-ranked memory modules, the dual-ranked memory modules must be installed in bank 1.
l Dual-ranked memory modules are not supported in bank 3.
l If dual-ranked memory modules are installed in bank 2, you cannot install memory modules in bank 3.
Memory modules marked with a 1R are single ranked and modules marked with a 2R are dual ranked. See Figure 6 -7 .
Figure 6-7. Determining a Memory Module's Capacity and Rank
Spare Bank Support
If six identical single-rank memory modules are installed, the memory modules in bank 3 (DIMM3_A and DIMM3_B) can function as a spare bank if you select
the spare bank option using the System Setup program.
Memory Mirroring Support
The system supports memory mirroring if identical memory modules are installed in bank 1 and bank 2, and no memory modules are installed in bank 3.
Table 6 -1 and Table 6 -2 show examples of different memory configurations. Table 6 -2 lists the various allowable combinations of single- and dual-ranked
memory modules.
Table 6-1. Sample Memory Configurations
NOTE: The memory modules must be PC2-3200 compliant.
NOTICE: If you remove your original memory modules from the system during a memory upgrade, keep them separate from any new memory modules
that you may have. Use only registered ECC DDR II memory modules.
NOTE: All six memory modules must be single-rank modules, identical in size.
Total Memory DIMM1_A DIMM1_B DIMM2_A DIMM2_B DIMM3_A DIMM3_B
256 MB 256 MB none none none none none
1 GB 256 MB 256 MB 256 MB 256 MB none none
1 GB 512 MB 512 MB none none none none
2 GB 512 MB 512 MB 512 MB 512 MB none none