The resolution you stream at heavily depends on your computer's specs as well as your internet upload speed. Here's a little more information about each resolution setting we offer (recommended upload speeds are based on streaming 1 camera and 1 capture source):
720p 30 fps (recommended) - This is the option we recommend for most of our users as it's an ideal bitrate for most broadcasts without transcoding options (ability to offer lower qualities to viewers with weaker connections). We recommend an upload speed of at least 5 Mb/s.
720p 60 fps/1080p 30 fps - This is a very high bitrate option, so viewers with poor internet may run into buffering issues. We only recommend using these resolutions if you're a partnered streamer on Twitch or are streaming on YouTube. We recommend an upload speed of at least 7 Mb/s.