very very new sorry but I have a question

so I just recently started mining with my gaming setup nothing fancy. just a gtx 1660 which gives around 20 mh/s. I was wondering if I add a second GPU such as a gtx 1660 super which according to some random googling has around 27 mh/s does that mean id be getting as much performance output as a card with 47mh/s or is there some sort of drawback (sorry for the lack of knowing much of what I'm talking about) if more info is needed to answer that question about my pc I'm happy to give it