Why is my computer is slow after installing an antivirus?

Updated: 06/30/2020 by Computer Hope
Antivirus programs and companies

After any antivirus scanner has been installed in a computer, it will be loaded into the computer's memory each time the computer boots. Loading the antivirus program into memory helps protect your computer at all times, from any threat.

When any program loads itself into memory, including an antivirus program, it will consume some of the total memory available to the computer. If your computer does not have lots of memory or is already low in memory, this can affect the overall performance of the computer.

Today, most computers have plenty of memory. However, they can still encounter a system slow down as the antivirus scanner is scanning all files on the computer to see if they're infected. You can check if the antivirus program is scanning your computer, stop the scanning, and change when and how often the scanning should occur. You may also be able to change how intrusive the scan is, in terms of how much memory it uses when scanning.

Change when and how often scan occurs

Your antivirus program allows you to change when a scan is done (i.e., time of day) and how often a scan is done (i.e., day of the week). As each antivirus program is different, general steps are provided below to help you change the scan frequency.

  1. Open the antivirus program's console by right-clicking the icon associated with the antivirus program in the Windows Notification Area (bottom right portion of the screen).
  2. In the antivirus program menu that opens, select Properties, Settings, Control Center, or something similar.
Tip

You may also be able to double-click the antivirus program icon in the Windows Notification Area to open the console.

  1. In the antivirus program's console window, look for an option to update the scan schedule. It may be named "Scheduler" or similar. The option may be located in a Settings or Advanced Settings section.
  2. In the current scanning schedule, modify the scan schedule to a frequency of your choosing. We recommend the scan run at least once every two or three days, to keep your computer protected against virus threats.

For example, users of the AVG antivirus program can adjust their scan schedule by following the steps below.

  1. Right-click the AVG icon (AVG icon) on the Windows Notification Area.
  2. Select Launch Test Center.
  3. In the Test Center, under the Scheduled Tasks, you can adjust when and how often your scan runs. If you want to disable the daily scan, double-click the scheduled task, click Edit Schedule, and uncheck the box.

Change scan intensity

Some antivirus programs may allow users to change the intensity of the scan, the amount of computer memory that is used during the scan process. Adjusting the scan intensity helps prevent the computer from becoming very slow during the scan process.

Note

Your antivirus program may not provide the ability to change scan intensity, so the steps below may not be applicable for your computer and antivirus program.

  1. Open the antivirus program's console by right-clicking the icon associated with the antivirus program in the Windows Notification Area (bottom right portion of the screen).
  2. In the antivirus program menu that opens, select Properties, Settings, Control Center, or something similar.
Tip

You may also be able to double-click the antivirus program icon in the Windows Notification Area to open the console.

  1. In the antivirus program's console window, look for an Advanced Settings option or section.
  2. In the Advanced Settings, look for a section named "Scan Settings" or "Scan Quality".
  3. Look for a checkbox or drop-down menu that allows you to change the scan intensity to a lower setting or low memory usage option.

Additional information