Streaming is not possible, Internet or PC?

Moin, have a question:

Have recently tried to stream Fortnite on my PC, have put in the OBS to 720p (Resolution 1280x720 then), as my stream has gelaggt. Habs then up to 638x570 or so put, but it still jerky a bit. Is that due to the weak performance of my PC or on my Internet?

How should we know if it's up to your PC or the Internet if you do not write what kind of a line you have or what PC hardware you have.

Which internet connection do you use?

Which ISP do you use?

Download 40-60 mbps, upload 10 mbps