If you are a Windows 8.1 user and happy with its default antivirus protection, which is provided by Windows Defender, then you can tweak its update frequency to get the updated security signatures faster. By default, Windows Defender updates them once in a day. There is an easy way to change this behavior.
Run File Explorer, and right click the This PC item. From its context menu select "Manage".
Tip: Here's how to tweak your PC to ensure top performance for a specific type of task, be it gaming, document work or something else.
The Start a program page will appear on the screen. Specify the following application as a "program/script" value:
C:\Program Files\Windows Defender\MpCmdRun.exe
In the Task properties dialog, switch to the Triggers tab and modify the trigger. Check the "Repeat task every" option. Set the frequency in hours for the signatures update to a value you want. In the following example, I set the update to be launched every 5 hours:
That's it! Another positive effect from this trick is that you will get updated signatures even you have disabled Windows Update. This trick will work in Windows 8 too.