Well explain me the difference between this:
a) 320x240
b) 640x480
b) 1280x960
(notice the 2x multiplication all the way, 240x2x2=960 and so on)
These three will always give the same results. At a) you represent one pixel in the image with one pixel on screen. At b) you simply use four pixels, all pixels are now four times smaller. So four pixels with the same color on screen show exactly the same as one pixel in a).
At c) it is the same, except you now use 4x4=16 pixels on the screen for each pixel in the image.
All these modes views the exact same, impossible to tell the difference. In theory, but if you have a screen like mine it interlaces at the lower resolutions so there still is a way to tell the difference...
And of course the 3D looks a lot smoother on the higher resolutions. And you have the *optional* ability to smooth the pictures out using some filter.
I agree that 800x600 it might look a little different, but smoothing filters will usually take care of that.