That's indicative of your computer being busy handling background tasks / processes.
You can use Resource Monitor to examine your cpu, disk, network and memory items to see what has your computer so busy
Control Panel\All Control Panel Items\Administrative Tools\Resource Monitor
A new install will stay pretty busy for as much as an hour or two but the intense activity should subside gradually over time.
IF not you may want to perform a clean boot
https://support.microsoft.com/en-us/kb/929135
And see if you can zero in on the offending culprit.