First of all, you should reduce the frames per second value in the “Output video settings”. How to get optimal value - look at the My video lags and freezes, how to fix? topic.
If the problem still remains, try to change the process video mode in the “Video” tab of settings, but don't increase FPS.
Still no result? Go to the “Recording” tab in the settings. Change the switcher of Desktop Duplicator API. If in your case Desktop Duplicator API was turned off by default and you have 2 graphics cards try to disable one of them(disable discrete card first)