Default [Q] Rendering some apps in 720p

I am wondering if there is any way to make some apps for example 3D games render in 720p instead of 1080p. This could be usefull for more performance in some games that could use that or to conserve battery while gaming, because the GPU can then work at a lower frequency and a lower voltage.

I know it is possible to make apps run in custom dpi settings
But I would like to know if there is any way to run an app in an custom resolution like 1280x720 or 800x480.

My I9505 is rooted, running KT kernel and its on 4.4.2 touchwizz.
My devices: Galaxy Gio Galaxy S Advance Galaxy S4 (I9505) White Frost 16GB