Whenever I try to browse on my laptop, the browsers (all of them - I've tried IE, Firefox, Opera and Chrome) keep on freezing randomly every 20-30 seconds for about 5 seconds. At the same time, I could see the same in steam - the game download speed at the very same moments suddenly drops to zero, and then goes back up. All the other applications work fine and even steam downloads work fine as long as I don't use the browsers.

This is a brand new laptop and I've done a full antivirus scan, so it's definitely not a malware/virus issue.
I've been using the same internet cable with my windows 7 laptop for around a year, and never had a single issue with browser freezing.

Any advice on how I could try to fix this?