5 Reasons Your Computer Is Running Slow

Your computer is running slow–like an old Pentium 2–despite having run lightning fast a year ago. You haven’t changed anything. Your virus checker comes up clean. What happened? This is a common problem that every computer user faces. Before you resort to smashing your computer with a sledgehammer, there are simple steps to revealing why your computer is running slow.

Here are five often-overlooked reasons why your computer is running slow.

#1: Your Computer Is Running Slow Because There’s No Space For The Page File

Have you noticed the huge increases in the amount of computer memory (RAM) shipped with computers over the last decade? My current computer has almost 1,000 times as much memory as my first computer. This is in part a result of greedy programs that want to use as much RAM as they can. If your computer is running slow, having as much RAM as your computer can handle installed, will definitely guarantee that your computer will run faster.

Windows is responsible for distributing RAM to each program. So, what does Windows do when it runs out of spare RAM to distribute? It tells programs to write their least-important memory to a special file on your disk called a page file. As long as there’s enough space in the combined memory and page file to hold every program’s memory, Windows doesn’t have to do anything further.

But, when you run low on disk space because your filesystem is filled up, Windows can’t create a page file large enough to hold any significant amount of program memory. That forces Windows to tell programs that they can’t have all of the memory they need.

Different programs handle low-memory situations differently, but every program must run at least a little slower. Some memory-hog programs, such as modern Web browsers, will run a lot slower when they can’t have all the memory they need.

The solution to this problem is easy: make sure you always leave a little free space on your filesystem. Ideally, you want to leave free an amount equal to the amount of RAM in your computer–so if you have 4 GB of RAM, make sure you always have at least 4 GB free disk space to prevent your computer from running slow.

#2: Your Computer Is Running Slow Because You Have Bad RAM

In at least one way, computers are remarkably like people: we get very upset when we can’t remember something. Bad computer memory (RAM) prevents software (including Windows) from running correctly, so computers spend a lot of time trying to find bad RAM. Modern computers can often work around bad RAM, but the workarounds may significantly slow down your computer–especially if the rest of your RAM is slowly rotting.

There are three times during which you computer can detect bad RAM:

  1. Boot up testing runs a very quick test over RAM, plus a more comprehensive check on a tiny bit of RAM used during the boot process. Any bad RAM found here will be disabled until the next time you turn on your computer.
  2. Write errors occur when a program tries to write to RAM. All well-written programs programs report these errors to Windows and ask Windows for permission to write to another part of RAM. Windows keeps track of these errors and tries to avoid using that part of RAM again.
  3. Read errors are the the worst–they occur when a program tries to retrieve something it previously stored in memory. When it gets an error and realizes it won’t get the data back, the program may crash. Other programs print obscure errors. Some programs may continue to try running and fail minutes or even days later for no apparent reason.

Windows can’t automatically detect read errors, so it will keep assigning the bad RAM to one program after another, possibly making your computer unusable.

All three errors can guarantee that your computer is running slow. Testing and write errors force Windows to keep track of bad RAM (which ironically takes up more RAM) and to assign RAM to programs in smaller, slower blocks. Read errors slow you down by forcing you to recover from program crashes and to deal with strange errors.

How To Fix Bad RAM When Your Computer Is Running Slow?

There is no way to fix bad RAM except by replacing it. What you can do is determine whether bad RAM is causing your problems using a free memory tester. I highly recommend the free Memtest86 program available on memtest86.com. Download the bootable CD image for Windows, burn it on to a CD, and put it in your CDROM drive. At the end of the day, reboot your computer and let Memtest86 run overnight. It will tell you the next morning if it finds any errors. Remove the CD and reboot your computer again to get back to Windows.

#3: Your Computer Is Running Slow Because Your Files Are Fragmented

When you create or save a file, Windows writes the new file starting at the end of the old file. This keeps all the files on your computer’s hard disk close together, but it means that if you increase the size of an old file–say by adding an extra sentence to a Microsoft Word document–Windows needs to split the file into two parts.

Windows hides this split from you–it even hides it from Word–but it still exists. This sort of file splitting is called fragmenting a file.

Fragmented files take longer to load because your hard drive needs to skip around to find each part of the file. You can easily eliminate most file fragments by running the Windows defragmentation tool: from your desktop, open My Computer, right-click your disk and choose Properties, choose the tools tab, and click Defragment Now. It may take several hours to defragment, so we suggest you defragment over night.

To prevent your computer from running slow because of file fragments, we suggest you run the defragmentation tool once a month.

Here is a link to my computer maintenance tips and tricks and my computer maintenance checklist.

#4: Your Computer Is Running Slow Because of Data Cable Cross Talk

You may have noticed that a lot of USB devices take the same cords, but you may not realize that the cords used for high-speed USB disk drives include special hardware to ensure they run at the highest speed possible.

your computer is running slow

Take a look at the USB cords around you. Notice that some of the cords have an approximately 1-inch (3-centimeter) cylinder near one or both ends of the cord. In this cylinder are several magnets. (If you have a magnet handy, go ahead and hold it up against the cylinder on a disconnected cord to see for yourself.) This magnet reduces interference (cross talk) from other nearby USB cables.

If your USB disk drive connects to your computer without cross-talk protection, it could run at as little as half its maximum speed. If you connect the drive to a USB hub, you also need to make sure the hub’s cable includes the interference-reducing magnets. High-speed disk drives are supposed to come with these special cords, but if you lose the cables, you can buy replacements for as little as $1 for each cord.

#5: Your Computer Is Running Slow Because Your Disk Drive Is Failing

By far the most common way for disk drives to fail is by wearing out the tiny ball bearings upon which the disks rotate. It’s these failed ball bearings that cause the distinctive groaning and clicking noises of a failed drive. Sometimes it is possible to fix failed hard drives but this is usually a job for the pros. Therefore if you notice the signs you should start to backup data just to be safe.

Computers Sometimes Run Slow Because Disk Drives Fail

Ball bearings don’t wear out all of a sudden; they wear down slowly over time. As they wear down, the performance of your drive slowly degrades until, one day, the tiny motor in your drive doesn’t have enough power to spin the drive anymore.

Your disk drive keeps track of over a dozen statistics related to its performance, called Self-Monitoring Analysis and Reporting Technology (S.M.A.R.T). You can access these statistics using special software–for example, DiskCheckup from Passmark.com.

The results reported will include a description of the state of the drive based on several criteria. You want to look the closest at the Throughput Performance (ID number 02) to figure out if the reason your computer is running slow is its hard disk.

If you have checked all these possibilities and your computer is still running slow then I recommend you also read 10 tips to speed up your computer. You might find another reason why your computer is running slow.

Install a program to do it all for you! Speed up your computer!

A software program will not upgrade your memory but it will clean out all the junk files, detect Malware, delete unused registry keys, Automatic Driver updates, and more.  At the moment I am using PC Matic to maintain everything for me. This software is amazing and has won a number of top awards. You can get a free scan for your computer to see how it works before you buy. That’s one way to speed up your computer.


  1. Vinay says

    Thanks David for this great article, My pc undergoes continuously with Blue screen error (Death screen). I have checked it and got my hard disk damaged. It was also slowing down my pc performance to fetch, retrieve data from disk…

  2. Mantu says

    My p4 pc sp2 40gb 128 ram ,pc processing is very slow there is no full memore in it why it run slow . Plz give me a solution how can i make little better fast with out changing ram

  3. Tom says

    Well, I was playing an online game (battlefield heroes) when my acer aspire 5536G randomly shut down without warning. When restarting it said I had to click start up repair but I decided to click start normally. After 5 minutes a blue screen with writing popped up and it restarted again, this time I used start up repair, and now my computer is so slow I am trying to delete memory and scan for viruses it is not working. Every click makes my laptop freeze for 5 minutes. PLEASE HELP :( I have vista

    • Nouda says

      If I recall correctly the random shut down is because of a failing motherboard. A lot of Acers that I know of (and used, twice) have had that issue and the only way to fix it is by replacing the motherboard itself; which is about a third or half the cost of of the original laptop price… When you’ve reached that stage it’s cheaper to get a new laptop.

  4. Bob Brown says

    Thanks I got a general idea.My computer is slow,I have no problem when I get on the internet.For example when I try to go into microsoft word it takes a while to boot up and the same way when I turn off my computer,I have ran a virus scan and defanged and cleaned up my disk drive,anything else I can do?

    • says

      Hi Bob
      Yes there are heaps of things you can do. See the link below for more information. The cleaning out of junk files and so on has to be done often along with other tasks..

  5. says

    I think all of those are very important factors for making your computer run faster, something else I would recommend is to check for viruses and spyware, because they also can slow down your computer. Thanks for the tips!

  6. peter rawcliffe says

    hi :) can you help me? when i got my pc it had internet explorer on it but i didnt like its speed,so after a few months i decided to add `google chrome` and this seemed much better and faster..slowly though things arent working so well and my videos play poorly if i watch them on youtube and also their is a clicking sound going on and the video stop and starts and jumps as well.i can surf the net with no problem but its just listening to radio stions or playing videos on youtube that work slow and play badly..should i delet my old internet explorer browser from my system? is this causing the problems by having 2 browsers? also if i do delete `internet explorer` will i lose programs and other things i downloaded when i only had the `internet explorer` browser?

    thanks,your advice will be most appreciated.


    • says

      Have you try using Firefox as your browser? that is my favorite and I almost never have a problem with it, as far as uninstalling chrome or internet explorer the thing that will loose are your favorites and addons, so I would do a backup of your favorites before uninstalling and I don’t think having more than two browsers would be any problem as far as the noise you hear when you play videos or listen to music, I’m not sure, but i would check your soundcard or cables. Try installing firefox and see if it solves the problem, also check if you have the latest version of flash installed.
      Good luck!

  7. Tom Drake says

    (o_0) Here’s my list! 1. Start-Up Programs/Toolbars/Crap Programs 2. Viruses/Spyware 3. Clogged Fan/Dead Fan/ Causing the processor to clock it’s self back to protect it from over-heating 4. Window’s Updates/Bloatware 5. Not enough ram/Bad Ram 6. Page filing Problems/Space Issues 7. Failing Hard-Drive 8. Idiot User/Owner…doesn’t even know how to properly use the dang thing & they go in & screw everything up!!! You can always tell if it’s gonna be a #8 because they’re the one’s that say they think it’s because they have too many saved e-mails…roflmao!!!~: )~*

  8. says

    There’s another option that is probably my problem.
    Your computer is running slow because it is old and slow.
    I’m thinking about getting some extra ram as I like to run a lot of programs at the same time, have two browsers with more than 5 tabs each open at the same time.
    I have 4gb ram now, And am thinking about getting 2x 4gb (I’m using a laptop)
    But after using this laptop for 2 years I’m afraid my hdd is going to fail.
    Is it possible to make a backup or image of this hdd and then buy a new hdd and put the image on that, then put it in the laptop and have my laptop exactly the same as it is now?

  9. says

    This tips is important for any one . Because personally use pentium 4. so i need to speed up my pc. I think this blog will help me to do so.