Ddr2 Memory Overview; Addressing Memory Configurations - Dell OptiPlex 755 User Manual

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Memory
User's Guide
You can increase your computer memory by installing memory modules on the system board.
Your computer supports DDR2 memory. For additional information on the type of memory supported by your computer, see the appropriate specifications for
your system in this book.

DDR2 Memory Overview

When installed in pairs, DDR2 memory modules should be of matched memory size and speed. If the DDR2 memory modules are not installed in matched
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pairs, the computer will continue to operate, but with a slight reduction in performance. See the label on the upper-right or upper-left corner of the
module to determine the module's capacity.
NOTE: Always install DDR2 memory modules in the order indicated on the system board.
The recommended memory configurations are:
A pair of matched memory modules installed in DIMM connectors 1 and 2
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or
A pair of matched memory modules installed in DIMM connectors 1 and 2 and another matched pair installed in DIMM connectors 3 and 4
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NOTICE: Do not install ECC memory modules.
If you install mixed pairs of PC2-5300 (DDR2 667-MHz) and PC2-6400 (DDR2 800-MHz) memory, the modules function at the speed of the slowest
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module installed.
Be sure to install a single memory module in DIMM connector 1, the connector closest to the processor, before you install modules in any other
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connector.
.
A matched pair of modules in DIMM connectors 1 and 2 (white securing
clips)
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.

Addressing Memory Configurations

If you are using a 32-bit operating system such as Microsoft
B matched pair of memory modules in DIMM connectors 3 and 4 (black securing
clips)
®
Windows® Vista®, your computer will support a maximum of 4 GB of memory. If you are using a