720p 2,500kbps 30fps, audio at 128kbps and then hit the preview. then open your performance tab for the cpu by holding down ctrl + shift + esc
adjust your "preset" to the slowest you can go (while gaming) before hitting 85% cpu usage.
anything above 85% can cause the stream to drop frames but it will not show on obs.
once you're maxed out, always keep obs minimised OR right click the video and disable the video preview and never watch your own stream. via the site.
doing either will use up more gpu/cpu.