Why is My Computer Suddenly So Slow? Do I Have a Virus? (part 2 of 3)
by Andy Trask

In the last issue of A Geek Told Me I discussed how one or more of many computer viruses could be the cause of a sudden and inexplicable slow-down of your computer. Of course as much as the viruses get the national headlines, there are two other very common culprits that can cause similar problems. The first is a shortage of memory, and no, I'm not referring to the fact that you can't find your car in the mall parking lot. I'm talking about your computer's Random Access Memory (also known as "RAM" in geekspeak) which makes up the space where your computer does all its work. The other possible culprit of course is the ever-present curiosity of a young child, or if you're lucky enough to have teenagers, perhaps you've already recognized your child's overwhelming need to download and install every piece of software ever written. But that's fodder for the next issue of AGTM!

So let's examine this RAM memory thing and see if we can figure out why your computer is slow. Think about this: RAM is the space on your computer where all the bits and pieces of data are temporarily stored and manipulated by the processor as you work on a document, browse the web, play a game or write an email to a friend. Because RAM memory is mind-bogglingly fast, your processor has no trouble whipping those little bits of data into a frenzy of organized "thought," arranging and rearranging data at lightning-fast speeds so you can interact with your computer in the intended fashion. The problem with RAM however, is that there is a limited amount of it in your computer, and each program you start or window you open "uses up" some of it, leaving less and less space for the processor to perform its critical bits-and-bytes juggling act.

Early on in the development of the Personal Computer, enterprising engineers recognized this limitation of RAM memory and devised a method to allow you to continue working or playing at your computer even when the amount of free RAM memory is getting low. What they did, and this is a standard feature in Microsoft Windows, is create something called a "swapfile" on your hard disk. The disk space in the swapfile is configured by Windows to look like additional RAM memory and is used by the computer as a supplement to RAM memory. This means as your computer starts to run out of RAM memory, it begins "pretending" that the swapfile space is really more RAM memory. The happy result is that you can use more, larger and more sophisticated programs than your computer has the RAM memory to handle.

The downside to this otherwise marvelous feature is that access to a hard disk is several orders of magnitude slower than access to RAM memory. Although you can run programs that are well beyond the capabilities of your machine, the overall performance of the machine is significantly impaired. Operations that would normally take nanoseconds to execute in RAM memory take milliseconds to execute on the hard disk (now humor my geekiness for a second by letting me explain). A Nanosecond is a billionth of a second and a Millisecond is a thousandth of a second. So to put things into perspective, that makes access to RAM memory roughly a million times faster than access to the swapfile substituting for RAM memory on your computer. Or, to really put things into perspective, that means if your computer is running out of RAM memory and is swapping memory out to disk, certain functions of your computer are running about a million times slower than normal!

So how do you know if this is the problem? Well, first of all, pay attention to your hard disk access light and the sounds your machine makes. Does it seem to be crunching endlessly while your screen takes forever to redraw or update information? Does your hard disk get accessed every time you try to type something? Does it become even worse if you have several programs open at once? If this sounds familiar, then chances are your system is swapping memory to disk and in most cases a simple RAM memory upgrade would get your system back up to speed.

Andy Trask is the Head Geek at Geek Housecalls (on the web at www.geekhousecalls.com). Based in Lexington Mass, Geek Housecalls provides computer hardware and software troubleshooting, networking, installations, upgrades, and general assistance to residential and small business computer users in Boston and the surrounding North, South, and Western suburbs as well as Rhode Island and southern New Hampshire. If you have a question or topic you'd like to see addressed by The Geeks, please send email to: agtm@geekhousecalls.com

If you're interested in reprinting this or other articles from this series on a website or in a printed publication please contact Andy Trask at andy@geekhousecalls.com for information about our liberal sharing policy!

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