Memory

Portable systems need extra memory as much as desktop systems do, but portable memory is both more expensive and less versatile than memory for desktop systems.

Generally, portable systems have only one connector for additional memory. Older portable systems might use proprietary memory modules, whereas recent systems use SODIMMs (a reduced- size version of an SDRAM or DDR DIMM module).

Portable Memory Module Types

The best memory upgrade for a portable system is to add the largest memory module (in MB) that can be installed in the system. Because a future memory upgrade would require the removal of the original memory module on systems with a single memory upgrade socket, it's best to add all the memory a system can take from the beginning. Figure 12.12 shows how a proprietary module and SODIMM compare to a 72-pin SIMM and 168-pin DIMM module.

Figure 12.12. Proprietary (top left) and standard SODIMM (bottom left) memory modules compared to 72-pin SIMM (top right) and 168-pin DIMM memory (bottom right).

Upgrading Portable Memory

Memory upgrades often can be performed without removing the keyboard, which covers most other internal components . Follow these steps to perform a typical memory upgrade:

1. Remove the cover over the memory upgrade socket on the bottom of the system.

2. Remove any screws or hold-down devices.

3. Remove the old memory upgrade if necessary.

4. Insert the new memory upgrade, making sure the contacts (on the back side or edge of the module) make a firm connection with the connector.

5. If you are installing an SODIMM or small-outline Rambus module, push the top of the module down until the latches lock into place (see Figure 12.13).

   Figure 12.13. Installing an SODIMM module on a typical portable computer.

   

6. If the memory socket uses screws to secure the memory in place, install them.

7. Test the module by starting the system and observing the memory counter; use third-party diagnostics if possible.

8. Close the cover and secure it to complete the upgrade.