There could be several reasons why your computer could be running slow. The number 1 issue is that you have too many applications/Chrome tabs opened. The more applications/Chrome Tabs that are opened the harder the computer has to work and the more resources it uses, which can cause slowness.

If you computer is only slow while using Google Chrome, make sure Chrome is up-to-date. This could also be an issue with your internet connection not being fast/strong enough, for this you would have to contact your internet provider to see if you are getting the speeds you are paying for.