Performance in huge window

[CacoFFF]

I just noticed that no matter the mode I try, it is ALWAYS scaled somehow (non-native res)
That happened after jpeterson started messing with the aspect ratios, you can clearly notice some blurness between some pixels.

I tried the various modes by pressing 4, they all scale.
Performance mysteriously increases by 50% if i enable native res.

I even tried running 320 x 240 on non-native, and was slower than 640 x 480 native on.