You can try playing The Vanishing of Ethan Carter on max settings, I think it uses the same engine that IdentityRPG is using and it could probably give you a good guess about how well your pc can run it. I know they are both different games so you most likely won't get the same performance but who knows. The Vanishing of Ethan Carter surprised me with how well it performed with such great detail and I am sort of expecting the same with IdentityRPG.