Internet works fine for every device, except my computer.

Hi guys,

So around 4 weeks ago, I got a new router and internet. The internet is working great for everyone on every device except for my computer. For some reason, my internet is not consistent with its ping (and this is just on my computer, the internet works great with my iphone). It almost seems like for every 1 minute of good internet I have, I have 10 or so minutes where the internet just stinkss. I am posting this on one of those good minutes. The problem started after I, 1. Got a new graphics card, and 2. Changed my antivirus software from Avira to Malwarebytes. If you guys need any more info just ask :D.

Thanks!