Macbook Pro Retina Slow Internet

The Internet on my Macbook Pro Retina 15" Mid 2015 constantly slows down about once a month, the only way to solve the issue is by deleting all the files in /Library/Preferences/SystemConfiguration/ then rebooting my Macbook. The issue then fixes itself until it happens again a few weeks on, does anyone have any idea why I'm constantly having to do this in order to get fast Internet?

Thanks