Total Defense is not really a serious AV, to be quite frank. There are better ones out there, even for free.
Regardless, as I and Krazy have already pointed out before and as I will do so again -- there is no reason for your PC to struggle that hard. It is not a misconfiguration or an error in OBS. Something really is wrong with that installation of yours and there is very little that we can say or do in addition to what has already been said and done.
Seriously consider re-installing Windows, avoid any trash AV's and be careful about your general PC use and configuration, that's about all I have left at this time.