Ask an expert: why is my computer so slow?


Computers, like people, age with time. They slow down, accumulate ‘junk’ and even get viruses. Here’s a few reasons why your computer may be running slow – and what you can do to fix it.

The main reason computers get slow (or sluggish) is because people don’t always follow basic maintenance routines. A computer is just like any other machine: it requires upkeep and ongoing care.

Below are a few things you can do to improve the speed of your Mac or PC. Note: these won’t help if you’re experiencing slow internet speeds – that’s a different problem entirely.

What to do if your PC is slow

PCs tend to be more prone to ‘ageing’ than Macs, but there are a few basic things you can do to improve the performance of your computer:

  • Turn off your computer. Make sure you turn off your computer at the end of each day so that the operating system (OS) can delete temporary files that clog up the paging files. Rebooting your computer often resolves issues like poor speed and performance; that’s why IT support often tell you to turn your computer off and on!
  • Clean up your hard drive. Your hard drive accumulates lots of files as it runs programs. That’s why you should use Disk Cleanup to remove unnecessary files and temporary files, and run weekly maintenance software such as CCleaner. This will remove the many small files that are downloaded as you browse the internet (called ‘cookies’), delete your download and browsing history, and clear the OS log files.
  • Defragment your hard drive. Over time, the files on your hard drive get ‘fragmented’ and your computer has to work harder to find them, which slows the whole system down. Defragmenting your hard drive every month ensures your files are accessible and easy to find. It can, however, take a long time, so consider using a tool like Defraggler – it works much faster than the Windows built-in functionality. (Note that defgramenting is not recommended on SSD drives as it could shorten its life expectancy).
  • Scan for viruses. A slow computer is a tell-tale sign of a malware infection. Run a regular virus scan and install anti-virus software to protect your computer.

Further reading:

Tips to free up space on your PC

Are Macs more secure than PCs?

Help, I’ve got a virus! What to do if you’ve been attacked


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What to do if your Mac is slow

  • Turn off your computer. Make sure you turn off your computer daily so that the OS can delete the temporary files that clog up the virtual memory.
  • Do a weekly permissions repair if you’re running OS X Yosemite or an earlier version of Mac OS. This makes sure that file permissions are set correctly, which is important for running software properly. Click here for instructions on how to repair disk permissions with Disk Utility.
  • Clean up the clutter. Your Mac gets clogged up with things like caches, logs, widgets, plugins, unnecessary files and apps, and that can slow it down. Run monthly maintenance software like OnyX  to remove the clutter. (One note of caution – always check the Smart status of your drive as well as the disk integrity as you launch OnyX).
  • Use Activity Monitor. Activity Monitor shows you what memory, network and disk processes are using up resources, and it also shows you how much CPU your programs are using. Take a look and ‘quit’ some processes and programs if they’re too resource intensive. Click here for instructions on how to quit a process in Activity Monitor, and read this guide to using Acitivty Monitor.
  • Scan for viruses. Yes, Macs can get viruses. A slow computer is a tell-tale sign of a malware infection. Run a regular virus scan and install anti-virus software to protect your computer.


Further reading

Use activity monitor on your Mac 

19 ways to make your Mac run faster

Are Macs immune to viruses?


Is it time for a new machine?

If your computer is more than five years old, it might be time to upgrade.

Ageing computers often can’t support newer operating systems, and the interruptions caused by slow machines may be more hassle than they’re worth. Upgrading may even be more cost-effective than sticking with your old machine: one study found that a small business with five computers (two of which are old) could save US$1500 by replacing old machines with new ones, thanks to reduced downtime and lower maintenance costs.

I’ve done these things and my computer is still slow!

If you’ve followed the above steps and still need help with a slow computer, reach out to us and we’ll help you.

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