Dell Inspiron 8600 Owner's Manual page 116

If you are replacing a memory module, remove the existing module:
8
a
b
NOTICE: If you need to install memory modules in two connectors, install a memory module in
the connector labeled "DIMM A" before you install a module in the connector labeled
"DIMM B." Insert memory modules at a 45-degree angle to avoid damaging the connector.
116 Adding and Replacing Pa rts
Use your fingertips to carefully spread apart the securing clips on each end of the
memory module connector until the module pops up.
Remove the module from the connector.
securing clips
(2 per connector)
memory module