Installing Dimms - HP dc7900 - Convertible Minitower PC Hardware Reference Manual

and the remainder is assigned to single channel. For optimal speed, the channels should be
balanced so that the largest amount of memory is spread between the two channels. If one channel
will have more memory than the other, the larger amount should be assigned to Channel A. For
example, if you are populating the sockets with one 1-GB DIMM, and three 512-MB DIMMs,
Channel A should be populated with the 1-GB DIMM and one 512-MB DIMM, and Channel B should
be populated with the two 512-MB DIMMs. With this configuration, 2-GB will run as dual channel
and 512-MB will run as single channel.
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In any mode, the maximum operational speed is determined by the slowest DIMM in the system.

Installing DIMMs

CAUTION:
Regardless of the power-on state, voltage is always supplied to the memory modules as long as the
computer is plugged into an active AC outlet. Adding or removing memory modules while voltage is
present may cause irreparable damage to the memory modules or system board.
The memory module sockets have gold-plated metal contacts. When upgrading the memory, it is
important to use memory modules with gold-plated metal contacts to prevent corrosion and/or oxidation
resulting from having incompatible metals in contact with each other.
Static electricity can damage the electronic components of the computer or optional cards. Before
beginning these procedures, ensure that you are discharged of static electricity by briefly touching a
grounded metal object. For more information, refer to Appendix D,
on page 57.
When handling a memory module, be careful not to touch any of the contacts. Doing so may damage
the module.
1. Remove/disengage any security devices that prohibit opening the computer.
2. Remove all removable media, such as diskettes or compact discs, from the computer.
3. Turn off the computer properly through the operating system, then turn off any external devices.
4. Disconnect the power cord from the power outlet and disconnect any external devices.
CAUTION:
power to drain before adding or removing memory modules. Regardless of the power-on state,
voltage is always supplied to the memory modules as long as the computer is plugged into an
active AC outlet. Adding or removing memory modules while voltage is present may cause
irreparable damage to the memory modules or system board.
5. Remove the computer access panel.
6. Locate the memory module sockets on the system board.
WARNING!
components to cool before touching.
18 Chapter 2 Hardware Upgrades
You must disconnect the power cord before adding or removing memory modules.
You must disconnect the power cord and wait approximately 30 seconds for the
To reduce risk of personal injury from hot surfaces, allow the internal system
Electrostatic Discharge
ENWW