SSAA is broken, that's why your screenshots are full of jaggies.
If you use a higher Internal Resolution than your monitor, then the Internal Resolution will be downsampled to your monitor resolution.
You might notice less aliasing when looking at your monitor, but unless you use anti-aliasing, there will always be aliasing.
As for Dev1L's claims. There is a enormous difference between the window sized shot and the 4x IR shot.
Naturally the 4x IR shot has a lot more detail (compare Melia on both shots) and the textures are more detailed too. The lighting is exactly the same in both shots.
Using multipliers (x2, x3, x4) is recommended over using window size as it might break some post-processing effects and such.
Most of the time though, you should be fine with window size. (Make sure you use the multiples of *** option).
If you use a higher Internal Resolution than your monitor, then the Internal Resolution will be downsampled to your monitor resolution.
You might notice less aliasing when looking at your monitor, but unless you use anti-aliasing, there will always be aliasing.
As for Dev1L's claims. There is a enormous difference between the window sized shot and the 4x IR shot.
Naturally the 4x IR shot has a lot more detail (compare Melia on both shots) and the textures are more detailed too. The lighting is exactly the same in both shots.
Using multipliers (x2, x3, x4) is recommended over using window size as it might break some post-processing effects and such.
Most of the time though, you should be fine with window size. (Make sure you use the multiples of *** option).