If i was you i will: Test another game non-origins with everything on ultra if problem persist. If it happen on another game: Scan and clean every virus NOT AVAST (avast are like donald trump and your origins game like joe biden you avoid to put them together) , run a CCleaner, Geting on amazon a ugreen wire hdmi or displayport (a quality one). Reset the bios and everything you have mess with (clocking, underclocking, you have changed stuff there you said). Reset all nvdia config you have changed( if you did it for da:i maybe u have done it on other game too). Install program monitor GPU temp and clean it (if you have a cat you will have a 2nd cat stuck under the fan of the gpu trust me).
You said: you can run any other game. but maybe something have broken after you start played inquisition , so test again the other game to be sure you can run them.
