Nx SSAA vs Nx IR : pros/cons?

[bLUEbYTE]

Pretty much as in the title.

Is there a compatibility / or accuracy advantage between running games at say, 4x super sampling anti aliasing and 1x internal resolution, versus 4x internal resolution and no anti aliasing.
Are there any subtle differences that one should expect with any graphics artifacts and overall image quality?

What about a compromise such as 2x SSAA & 2xIR?

[MayImilae]

There is no compatibility or accuracy improvement to running at lower internal resolutions. We only scale up by integer values (2x, 3x, etc) specifically for this reason!

As for image quality, for best results you should set your internal resolution to match the native resolution of your display and then add antialiasing.