Windows Defender is a malware scanner & remover from Microsoft and is installed by default on all system. In my opinion, I think this software poorly do the job and also can cause trouble when using along with third party anti-virus. That is why I recommend everyone to disable it, or not if you do not have any anti-virus, anti-spyware third party software.
How to disable Windows Defender on Windows 8 ?
1. Open control panel and select ‘Windows Defender’.
2. Select ‘settings’ tab.
3. Click on ‘administrator’ on the left pane.
4. Turn off (uncheck) the following : ‘Turn on windows defender’.
5. Windows Defender is now off.
It’s as simple as that. You should notice gain of speed if you had a third party anti-virus running.