Nah, not really. Technically VPN makes it to slow down for these reasons. 1) The ads (if you're not using premium editions) use some trafic. 2) when you're using VPN 3rd party is involved ( a web server probably far away from you're location; that's the case most time). And this introduce a lag because each request/response is using a route that include the 3rd party. Longer route means more traffic/slower speed.