Most PC games change the rez to correspond to the internal rez being used. But why? It's because it fills up the balloon more making it less shriveled. It greatly increases image quality while at the same time, helping the user to use LESS post processing effects to completely rid your image of jaggies! Pete's 2.9 gpu plugin for epsxe does this internally already. Here is the proof of concept that works with mostly any game you have (even pc games that don't change desktop rez already)...
ShinRa Enterprise
ShinRa Enterprise