Dell Dimension C521, Owner'S Manual, Page: 65 / 140

Removing and Installing Parts
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• A pair of matched memory modules installed in connectors DIMM1 and DIMM2 and another
matched pair installed in connectors DIMM3 and DIMM4
• If you install mixed pairs of DDR2 533-MHz (PC2-4300) and DDR2 667-MHz (PC2-5400) memory,
the modules function at the slower installed speed.
Be sure to populate the memory modules in order starting with DIMM1, the connector closest to the
edge of the system board, before you install modules in the other connectors.
NOTE:
Memory purchased from Dell is covered under your computer warranty.
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.
Installing Memory
CAUTION:
Before you begin any of the procedures in this section, follow the safety instructions located in the
Product Information Guide .
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)
1
2