CGI cutscene aliasing/low resolution

[LunaMoo]

By cutscenes you probably mean movies. Even if they often were made in game engine and look similar to the rest of the game they are actually pre-rendered so no suprise that rendering resolution has no effect on it.
If you even see a difference by changing resolution it's just caused by screen scaling filter which by default blurrs everything up when you mix small rendering res with high display res.