How to Increase the Memory Size of Your Desktop Computer

Often the fastest and easiest route to improving the performance of your desktop, laptop or server is to add more memory. This is especially true as you upgrade to new software, and it's even more likely to be true if you decide to use Vista. Here, Neal Nelson, president of Neal Nelson & Associates, explains just how to go about the process.


In some ways a computer is like a car because there are some changes and repairs that owners can perform on their own. Increasing the size of the computer's main memory (RAM) may be one of them.

CAUTION: By attempting the steps described in this procedure you may ruin your computer. Pushing too hard, or in the wrong place, can crack the computer's motherboard. A small spark of static electricity can burn out critical computer circuits. Installing a memory module "backwards" can cause short circuits. An improperly "seated" module can prevent the computer from booting when it is powered up. Be careful and good luck.

Step 1: Determine the Current Size of the Computer's Memory. For computers running Windows, Microsoft provides a program called Task Manager that provides a quick display of the system status. Run this program by clicking the right mouse button while the mouse pointer is positioned on the task bar (normally at the bottom of the screen) then select "Task Manager." Click on the "Performance" tab. Make a notation of the number listed for "Physical Memory (K) - Total." For computers running Linux, login as "root" and type the command "cat /proc/meminfo "; then note the value for "MemTotal."

Step 2: Locate the Memory Modules in the Computer. Power down the computer and unplug the computer's power cord. Open up the computer case and locate the computer's memory modules. Most computers have DIMMs (dual in-line memory modules) that fit into DIMM sockets. Look for the DIMMs and note: 1) How many DIMMs are currently installed; and 2) How many empty sockets remain with no DIMMs installed. Here is a picture of two DIMMs and two empty DIMM sockets.


Step 3: Plan Your Upgrade. Consider the total size of the computer's currently installed memory, the number of DIMMs currently installed, the number of empty DIMM sockets and the desired increase in memory size. DIMMs are often installed in pairs, so consider adding two 512MB DIMMs if you wish to increase the computer's total memory size by 1GB. You may have to remove some currently installed DIMMs to free up slots for the new memory modules that you wish to install. You must also determine exactly what type of memory you need. There is SDRAM, DDR, DDR2, DDR3, FB-DDR, Registered, Un-registered, parity, non-parity, ECC, non-ECC, 2.2 volt, 1.8 volt and 1.5 volt, plus a variety of speed grades like 512, 667, 800, PC-3200, PC-4800 and PC-6400. If you buy the wrong type of memory the computer may not boot or you might even "burn out" some components. Many computer and motherboard manufacturers have copies of manuals online that will provide the specifications for the memory modules that are compatible with the computer.

Step 4: Obtain the New Memory Modules. DIMMs are available from a number of sources. These include the companies that built the computer, such as Hewlett-Packard or Dell, retailers like Best Buy, online merchants like Dalco or Newegg, auction sites like eBay or craigslist, and special memory Web sites. The "safest" option is to purchase the new memory from the company that originally built the computer. Another safe, and usually less expensive, option is I generally recommend Crucial to someone that is new to upgrading memory. Crucial has an excellent online system to find the right memory module, it shows the detailed technical specifications for the recommended memory, it provides instructions on how to install the memory, it offers free shipping and it has a 30-day money-back compatibility guarantee.

Step 5: Install the New Memory Modules. The installation procedure is: 1) Be sure the computer is powered off and the power cord is unplugged; 2) Position the computer chassis so that you will be able to press the DIMM into the socket with a straight-down, firm and even pressure. I like to lay the chassis down flat on a strong table, or on the floor, so I can lean over the chassis when I press straight down; 3) Wear an antistatic wrist strap or touch the chassis frequently to drain static electricity; 4) Flip open the retaining clips at each end of the DIMM socket; 5) Orient the DIMM properly based on the notch on the DIMM and the corresponding bump in the socket; 6) Press the DIMM into the socket by pressing with one thumb at each end of the DIMM. There will often be a "click, click" as the DIMM seats down into the socket and the retaining clips snap into position. Be careful. If you press too lightly, or press unevenly, the DIMM will not "seat" and will not make proper electrical contact. If you press too hard you can ruin the motherboard by cracking it. This picture illustrates this step.


Step 6: Test for Proper Operation. Connect the computer's power cord and boot the machine. Repeat Step 1 to check if the new memory size agrees with your expectations. You might also want to run a thorough diagnostic test of the computer's memory. There are some low-cost and free test programs available from and Consider executing the test for many hours (like overnight).

Step 7: Possible Problems. If there is some problem during the upgrade, the computer may display a smaller-than-expected memory size, or it may not boot at all. Check very carefully to see if the DIMMs are properly seated in the sockets. You might also check to see if you have accidentally bumped some other card, like the computer's video card, so that it is no longer properly seated in its slot. Try removing the new DIMMs and booting with the original memory configuration. Consider contacting the company that sold you the memory. It might have a support center that could help you solve the problem. Otherwise it would be time to call a professional and ask for help.

A memory upgrade is a procedure with medium difficulty and moderate risk that can provide significant benefits for a modest cost. As I said at the start of the article, be careful and good luck.

{mosimage}Neal Nelson has more than 35 years experience with all aspects of complex computer systems. As the chief developer, owner and president of an independent hardware and software performance evaluation firm, he has tested more than 500 computer systems. Some of his test results can be found at For further information send an e-mail to