There are a lot of reasons behind the slow speed of the internet. You can check it here ptcl speedput. It can be your old router, your internet itself, and your distance from your router. I would suggest that you should use a wired connection because that’s how things in the middle of your device and the router won’t disturb the signals of the internet. You can also use a wifi booster for this purpose. Also, keep checking your internet speed to make sure that you are getting the actual speed of the internet.