Upgrading your computer memory for cheap performance enhancement is one of the best ways to ensure your PC stays current for as long as possible. Most systems come with significantly less memory than the motherboard can hold; meaning adding memory is a simple way to upgrade.
Before you buy memory sticks
Before you buy any kind of memory, there are two things you need to know. First, what is your system's capacity, and second, what type of memory does it need? To find out your computer model details, click on the start button in Windows 7, then right click on 'Computer,' and scroll down to the 'Properties' option. This should tell you the manufacturer and model numbers, as well as the version of Windows your computer is running, and whether it is 32-bit or 64-bit. It will also tell you how much memory you have installed. What it won't tell you is how that memory is configured and how much the motherboard can handle.
The quickest way to find out how much memory your motherboard can handle is to check the documentation that came with the computer. If you've lost this, use the manufacturer and model information from the computer properties screen. Visit the manufacturer's website, and type in the model number followed by the word 'specifications,' to find this out. This should also tell you which type of memory you need (DDR-RAM, etc). If you can't find your model number because it isn't listed in the computer properties screen and you don't have the documentation, you may need to open the machine to see for yourself what you have.
Buying new RAM sticks
Once you know how much RAM your motherboard can handle, how many slots you have, and which type of memory to buy, the rest is easy. A 32-bit Windows operating system can handle up to 4 Gigs of memory. If you have a 64-bit OS, and you have Windows 7 Home Basic, it will be able to handle 8 Gigs. Home Premium can handle up to 16 Gigs, and Professional, Enterprise and Ultimate editions can handle up to 192 Gigs. Check Memory Limits for Windows Releases to see how much RAM your OS can handle.
You don't have to fill every memory slot in your computer, and you can mix and match sizes with most, but you will achieve a better performance with 'exact match' memory. What that means is that your computer will perform better if every piece of memory in it is identical, the same capacity, same speed and from the same manufacturer. So if you have 2 Gig sticks and you want to upgrade to 4 Gig, it's always better to upgrade to two 2 Gig sticks or add another two 1 Gig sticks than simply adding a single 2 Gig stick to an empty slot.
Once you have your new memory sticks, fitting them is easy. Simply ensure the computer is switched off, and use a small screwdriver to remove the chassis. Ensure you are grounded, using a grounding mat and wrist strap to avoid static discharges, locate the old memory sticks and remove them. Replace them with the new sticks, ensuring they slot home fully, replace the chassis, and you are good to go.