Dell Dimension E521 - Memory Installation Guidelines

Removing and Installing Parts 71
Memory Installation Guidelines
• DIMM connectors must be populated in numerical order beginning with connectors DIMM_1 and
DIMM_2, then connectors DIMM_3 and DIMM_4.
If a single DIMM is installed, you must install it in connector DIMM_1.
• For best performance, memory modules should be installed in
pairs of matched memory size, speed, and
technology
. If the memory modules are not installed in matched pairs, the computer will operate, but
with a slight reduction in performance. (See the label on the module to determine the module’s
capacity.) For example, if you install a mixed pair of DDR2 533-MHz and DDR2 667-MHz memory,
the modules function at the slowest speed installed.
NOTICE: If you remove your original memory modules from the computer during a memory upgrade, keep them
separate from any new modules that you may have, even if you purchased the new modules from Dell. If possible,
do not pair an original memory module with a new memory module. Otherwise, your computer may not start
properly. You should install your original memory modules in pairs either in DIMM connectors 1 and 2 or DIMM
connectors 3 and 4.
NOTE: Memory purchased from Dell is covered under your computer warranty.
1 Channel A: matched pair of
memory modules in
connectors DIMM_1 and
DIMM_2 (white securing
clips)
2 Channel B: matched pair of
memory modules in
connectors DIMM_3 and
DIMM_4 (black securing clips)
2
1