I very much doubt that Windows8 is to blame.
You say you are "pretty sure its not the internet connection", but what makes you so sure? Both the uses you describe rely heavily on internet bandwidth to run smoothly, and if there isn't enough you will get the slow response times you mention.
Windows 8 is unlikely to be running "loads of rubbish I don't need", but your new laptop may well have stuff on it that fits that description. Take a look at the Windows8 start screen and see what software is installed. Right click or tap on the screen and select 'All apps' as well. You'll see everything that came with the computer, and you can uninstall anything you don't need