Hello,
Well for what is seems you have 11830 Kbps which is 11.83 Mbps. For such an upload speed, the bit rate you have set right now (3500) is too low which means that you are putting a lot of stress on your CPU in order to decode... IMO. Try raising the bit rate a little more and see how that works out for you. The greater the bit rate you have the less stress you put on your CPU. Also, if you are currently set up to stream at full 1080, you may want to try to step down to 720p at 30 FPS as that is the download capability that most people have to watch the stream. I know you used the estimator for this and I did to but once I raised my bit rate a little more, all my issues where resolved. Hope this helps
Good luck!