A PC running Windows can slow down for many reasons. Viruses, spyware, updated software, disk fragmentation, and more can lead to performance drops.
Slow machines represent one of the largest sources of questions to Ask Leo!
Perhaps when you purchased it, your computer ran like a champ and did everything you needed (and quickly). Now … well, not so much. Perhaps it takes forever to boot. Or starting applications is slower than molasses. Or maybe the machine just acts sluggish when you try to use it for just about anything.
Regardless of the specifics, the underlying theme is simple: it’s slow.
The problem is that there are many, many reasons that a machine could slow down.
I’ll try to list a few of the most common reasons here, along with some advice on what steps to take.
It’s a slow machine
An assumption I’m making here is that it’s your entire machine that is slow, not just one or two applications.
For example, if Internet Explorer has slowed down while the rest of your software runs just fine, then you’ll need to take a different approach than what I’ll outline here. You’ll need to focus on the specific applications that are behaving slowly. Perhaps some of the solutions may be the same, but arriving at those solutions and choosing one will depend a lot more on investigating the issue with that specific application.
Nope. Here, we’re talking about a slow computer, no matter what you do.
Sudden slowdowns: Malware comes to mind
In my experience, the number one cause of a system gradually slowing down over time is simply that it’s being asked to do more and more …
Different types of malware will, of course, do different things, but they’ll also often behave differently on different machines. One of the symptoms of malware can often be a suddenly slow or sluggish system
Of course, your anti-malware tools are your first line of defense. Make sure that they’re up-to-date and run scans using both your anti-virus tool and anti-spyware tool (assuming you’re using two separate tools). I’d also consider a run of the free tool from malwarebytes.org.
Naturally, I have recommendations for anti-malware tools .
Sudden slowdowns: A program run amok
Another step that I take when my machine seems to be slowing down, particularly if it’s sudden and unexpected, is to fire up Process Explorer. Very often, one source of a system slowdown can be attributed to a single program running on your machine that is attempting to use all available processing resources. When that happens, other programs (often including Windows itself) aren’t able to respond to your actions as quickly as otherwise.
How do I find out what program is using all my CPU? will walk you through the steps using Process Explorer to identify any processes that are in this state.
Similarly, a program that’s using the disk heavily (i.e. the activity light isn’t even flickering, it’s just on), or even using the network heavily can manifest as a system that is or seems slow. I have constant disk activity, and I don’t know why. How can I tell what program is doing it? and How do I monitor internet activity and see who’s using it? will help you identify those culprits, if present.
Sudden or gradual slowdowns: Impending hardware failure
This isn’t as common, but it definitely does happen.
We normally think of most hardware failures as sudden and catastrophic. Sometimes, they’re a little less catastrophic than we think.
For example, if a sector on a hard disk is going bad, that may first manifest as a slowdown whenever that sector is accessed. The disk drive will try multiple times to read a marginally bad sector before giving up and that takes time. If multiple sectors are affected (which is common if it’s an area on the disk media that’s been damaged, for example), then this might be happening for more than one and that time could be adding up. The system keeps working because the sectors aren’t so bad that they actually fail, but they take additional time to be read because they’re going bad.
Back up, of course. Impending failure can quickly become actual failure and data loss.
Gradual slowdowns: Too much stuff
In my experience, the number one cause of a system gradually slowing down over time is simply that it’s being asked to do more and more and it’s trying to run too much software simultaneously.
Over time, people ask their computer to do more and more.
Generally, folks find themselves in this situation after installing software on their machine that includes a component that always runs. Over a long period of time, there’s so much running on the machine even when it’s not in use that when it is in use, there’s not enough computer left over to run the desired programs quickly and efficiently.
Examples of software that might get installed over time? Webcam software after getting a web cam, instant messaging programs, Skype, Dropbox, Evernote, screen capture utilities, TrueCrypt, and so on. There are many possibilities and that doesn’t even take into account the ubiquitous software update checkers and quick loaders that so many software manufacturers seem fond of leaving around to run all the time.
There are two approaches to resolving the “too much stuff” scenario:
- Run Less Stuff: Start reviewing the list of software that’s running on your machine when you’re not doing anything (Process Explorer will help) and question everything that you’ve installed. Uninstall everything you don’t really need.
- Beef Up Your Computer: It’s a common adage that adding RAM to your computer is one of the quickest ways to speed it up and this is why. If RAM is a constraint for the software you’re running, then your computer will absolutely slow down. Adding RAM to your system, if it’s possible, just fixes that.
Gradual slowdowns: Fragmentation
It’s not the common problem that it once was (particularly with Windows 7 doing a defrag automatically now), but it’s possible that your hard disk has become fragmented. All recent versions of Windows have built-in defragmenting tools.
In Windows Explorer, right-click on your hard disk drive (normally C:), select Properties, and click on the Tools tab – there you’ll find the disk defragmenter. It’s a good tool to run periodically, although how often will vary depending on your computer usage.
Windows 7 will defrag your hard disk weekly, and if you’re running Windows Vista or XP, How do I schedule Disk Defragmenter to run with the Windows Task Scheduler? will let you set it up automatically as well. Windows 7’s choice of once a week seems like a reasonable approach.
Gradual slowdowns: Updates
In a sense, this falls into the “Too Much Stuff” category, but applies even if you haven’t made a single change.
It’s commonly understood that systems only tend to get bigger over time. That’s more-or-less the nature of software evolution and the expectations that we have of increasing functionality and support.
While we normally associate that with major version updates (i.e. Windows Vista was larger than Windows XP), it can actually happen – slowly – at the system or application update level as well.
Years worth of updates can slowly increase the resource requirements of your operating system and installed applications. Particularly if your system is already somewhat marginal, that increase can be enough to eventually impact your overall performance.
Note that I’m not talking about files left behind after an update (unless, of course, your hard disk is filled to capacity), but simply the scenario where the patched version of application “A” might need ever so slightly more RAM than before. Repeat that for all the applications that you have installed and the updates your system takes, and it can add up.
Once again, adding RAM can help if this is the case.