Memory is the part of your computer in which programs run and you write or modify your documents. It is not the same thing as storage (even though both are commonly measured in gigabytes nowadays). Storage is done on your hard drive, a small device in your computer that measures about 3-1/2 inches wide, 6 inches deep, and 1 inch tall. The hard drive is where the files and programs are stored once they are written to your computer and waiting for use.
Now that the easy part is answered, let's move on to the harder question: how much is enough? This depends on a number of factors: the version of the operating system installed, the programs you use with your computer, whether you have your video controller built into your motherboard, how many programs you wish to use at the same time, and what programs will be running in the background.
In regard to the operating system question, if you are still running on Windows XP, you will want a minimum of 1 gigabyte of RAM, preferably 2 or 3 gigabytes if the computer can handle it. (I'll explain this further in a moment.) Vista users, if you have less than 4GB, you should run out and get more memory now. Vista is a hog when it comes to memory (and for no good reason). This is one of the many reasons that I felt Vista was a bad idea and never recommended it to any of our customers. Windows 7 is better at memory handling than its predecessor but it still wants at least 4GB to be comfortable, 8GB is preferable, however. Finally, for Windows 10, 8GB is the amount you want. Anything less and the machine will be very slow and inefficient while more than that is just a waste of money unless you are a power user (such as an architect, 3D video editor, etc.).
Now, let's get back to Windows XP's memory requirements. Many machines, especially Dell computers, were manufactured with as little as 256 megabytes when brand new. If you look at the memory usage of such a machine with Windows' Task Manager, you will find that with only 256 megabytes of RAM and nothing running (the computer is just sitting at the desktop after just starting up), the computer has only about 20 megabytes of memory free. Considering that even a simple web browser such as Mozilla Firefox uses as much as 70-80 megabytes to look at the Internet, you can see that something has got to give. What gives (until the memory is upgraded) is the speed of the computer. Windows makes up for the memory deficit by moving necessary items in and out of the Windows swap file (which is a special file on the hard drive that is used by Windows as if it is memory). The problem is that hard drive access happens much slower than memory chip access: hard drive activity is measured in milliseconds (thousandths of a second) while memory access is measured in nanoseconds (billionths of a second). Thus, literally, the hard drive is a million times slower.
Okay, now you are convinced that you need more RAM but you think, "Eh, why go up to a full gigabyte? I can get another stick of 256 megabytes, double my memory, and make Windows happy, right?" Wrong! Windows is happier that you put in the additional memory but it starts using it for everything that it couldn't put into memory before. In fact, out of the total of 512 megabytes of RAM that you have theoretically installed, your available memory would be only about 100 megabytes, meaning that you could run one program in memory (say, Firefox) and that's about it. To keep the computer from bogging down, you would have to close Firefox to start up something else.
So, what happens when you take out the 256 megabyte stick and drop in a couple of 512 megabyte sticks to give you a full gigabyte of RAM? Windows still grabs some of it but not quite as much. With 1 gigabyte of RAM, most XP users have around 400 megabytes available for running various programs. If you intend to use a web browser, email client (such as Mozilla Thunderbird), Quicken (or QuickBooks), Windows Media Player, and maybe a few other things all at the same time, then your 1 gigabyte might start to seem puny and you might want to move up to 2 gigabytes by putting in two 1-gigabyte sticks of memory.
For later versions of Windows, starting with Windows Vista, the concepts above are the same but with amounts of free RAM and the amount of RAM used by the operating system varying. To put it simply, the more modern the version of Windows, the more RAM it will consume for its own basic functionality and therefore the more that you will need installed to give you the performance that you expect.
Okay, now to confuse things even more, there are two different versions of modern operating systems available: 32-bit and 64-bit. To put this in a nutshell, this determines the amount of RAM (and hard drive space but that is not pertinent to this discussion) that can be used. With a 32-bit operating system, the most memory that can be addressed is just a little under 4 gigabytes (in practical terms, we will say 3 gigabytes because of the designs of most motherboards). Under the 64-bit version of the operating systems, there is no practical limit to what can be used but there probably are for the motherboard (most motherboards manufactured today can address up to 32GB or 64GB of RAM, more than anyone with whom I have worked has needed for a typical computer; that much RAM would easily be used by a network server, however).
Okay, so we've discussed the operating system and the number of applications that one might wish to run. What does the video controller have to do with anything? I'm glad you asked! With desktop computers, there are two possible ways to get video to the screen: a video controller built into the motherboard (or CPU) and a video card plugged into one of the expansion slots. (If you have a typical laptop computer, there is no choice: your video is built into your motherboard. Some higher-end laptops have discrete video adapters but those are uncommon.) To determine whether your video is built into the motherboard of your desktop computer, take a look at the back of your computer and see whether the video cable from the monitor is plugged into a port that is grouped along with others fairly close to the power cord or whether it is perpendicular to the others and further down from the power cord than the other ports. If it is with the others, then it is built into the motherboard. Otherwise, it is an option card.
Now why does this matter? Because a video controller built into the motherboard has no memory of its own to use for displaying images. Thus, it has to "steal" it from the system memory. Most computers with such motherboards are set up to give at least 64 megabytes of RAM to the video controller. Therefore, if you have upgraded your theoretical Windows XP-based machine to only 512 megabytes, you are actually running with only 448 megabytes or less and your available memory is probably closer to only about 30-40 megabytes at most after that upgrade. This is yet another good reason to move up to a full gigabyte of RAM. For computers running Windows Vista or later editions, the amount of RAM used by the integrated video is most often not configurable but, in our experience, it is often as much as 512MB. Therefore, our minimum recommendations as stated in the third paragraph of this column are very important and should be considered carefully.
What about the specific programs that you might wish to run? Some are more demanding of memory space than others. For example, when I burn DVDs, it is not uncommon to see the burning software use 300 to 400 megabytes of RAM. On the other hand, if you are a professional photographer and use Photoshop to edit your top quality pictures or are an architect and use AutoCAD for your drawings, you may want to upgrade to 64-bit Windows 7 or 10 and put in no less than 8 gigabytes (preferably 16GB) as those applications can easily grab it all.
So, as you can see, when looking at memory upgrades, there are many various factors to keep in mind. The best advice is to get in touch with us at Best Deal Computers so that we can make sure to steer you in the right direction.