Windows reserve twenty percent bandwidth for windows update. Flowing this process and solve this problem-
Step2: Click Local computer policy.
Step3: Administrative Template.
Step4: Go to Network.
Step5: Qos Packet Scheduler > Left side reservable bandwidth.
Step6: Click Enable > Bandwidth limit > 0 > Press OK
Step7: Restart your computer.
When will restart computer then see Internet speed increase more than before. But set up windows system will changed.