applications shadowed every 5 minutes

Lately I experience a problem on my notebook running Windows 8: every 5 minutes the application currently running seems to be suspended for a while. For instance, I’m writing a document and for a few seconds the letters I type don’t write anything, and the title bar on the top of the document gets shadowed. I suspect it can depend on a background activity of the free avast antivirus, that seems to become the foreground application for a while. Every 5 minutes exactly. Someone can confirm my suspect or experienced the some problem?
Thank you in advance

Possibly when a streaming update occurs?