What you need to know about laptop memory.
Laptop memory is an important consideration when purchasing a laptop. Like the memory on a desktop computer, the random-access memory (RAM) on newer models is measured in gigabytes (GB). Older models specify the RAM in terms of megabytes (MB). A gigabyte is equal to 1,024 megabytes, and both simply describe the data storage ability of a computer.
A laptop with more RAM can run more applications simultaneously, so consumers should consider whether or not they frequently run multiple programs when choosing between different models of laptops with different amounts of RAM. Although the RAM can be upgraded later to increase performance, installation can be difficult on some laptops.
Notebook RAM uses a Small Outline Dual Inline Memory Module (SO-DIMM), which is about half the size of the modules used in desktop computers. SO-DIMMs, which are a type of computer memory using integrated circuits, are designed to fit in the limited space available to laptop computers. This makes them more expensive to produce than the larger desktop modules. The SO-DIMM modules are created with different pin configurations (72, 100, 144 or 200 pins), speeds and memory capacities. Speed is usually indicated by its clock-speed rating (DDR2 or DDR3) or by bandwidth (PC2 or PC3).
Speed and capacity provide the best performance indicators -- the faster the chip and the greater the memory capacity, the better the overall computer performance. Also, pin configuration is related to the rate of data transfer; the higher the pin configuration, the higher the data transfer rate. Older 72-pin DIMMs only support 32-bit transfers, while 144-pin DIMMs can handle twice the transfer rate.
Decisions about memory should be made before purchasing a laptop. Laptop memory is more expensive than desktop memory, but can have a significant impact on performance. Too little memory can cause applications to slow down and even crash, but purchasing too much memory can run up the cost of the laptop unnecessarily. Every application and game makes demands on memory, but video and sound processing have greater memory requirements. Consider the following factors when determining how much memory is needed:
According to PCWorld, laptops running Windows Vista should have 2GB of RAM. Most Macintosh laptops running OS 10.5 Leopard, or later, ship with 2 GB minimum. Notebooks running Windows XP require a minimum of 64 MB, although 128 MB is recommended. Older versions of Mac OS X require a minimum of 128 MB. Upgrades to more recent operating systems and current software releases increase the memory requirements (especially software suites that run multiple applications simultaneously).
Minimum requirements would be fine for e-mail, word processing and Internet browsing. However, users who want to use platforms intended to run processor intensive multimedia production applications may want to upgrade older laptops to run with as much memory as the model can carry.Right-click on "My Documents" on any laptop, select "Properties" and look under the "General" tab to see the current memory capabilities of the computer.
Laptops have more restrictions on memory than the typical desktop because space is limited. The number of slots available for expansion and upgrade on a laptop is fewer than on a desktop: laptops typically ship with no more than two slots for SO-DIMMs.
The particular computer configuration becomes especially important when upgrading memory. Laptop motherboards may require 72, 100, 144 or 200 pin SO-DIMMs, which are the memory modules in laptop computers. In addition, the new chips should match the speed of the chips that shipped with the laptop. Consult the owner's manual for the required chip specifications.
Local vendors and repair shops can install RAM at a reasonable charge, and reputable manufacturers will include memory installation instructions with the owner's manual or on their Web site. ComputerMemoryUpgrade.net offers the following generic tips for successfully installing new memory. Before installing or upgrading RAM, the computer should be powered down, the battery disconnected and all power cables removed. The cover panel for the memory modules must be removed; usually it can be found underneath the laptop. Most panels can be removed with a standard or Philips head screwdriver. The screws should be set aside to prevent loss.
Handle the new memory modules gently while doing the installation. Unfasten any clamps and lift out the old module at a 45-degree angle. Align the notch on the new module with the memory slot before slipping it in at the same 45-degree angle. Carefully assign the pins with the holes so they don't bend while inserting the new memory. Rotate the new module downward and press it flat until the lock snaps into place. Replace the screws and cover, and then plug it into a power source. Reboot the laptop to test the memory and make sure it works properly (some PC computers may need to search for the new memory in the system BIOS).