more pixels are better!

Iforgetwhat8was4 wrote:

The OP is really more interested in whether a 6Mp compact will be a
better all around performer than a 12Mp compact, or if this is just
an artifact of other design choices made that reviewers don't like.
In particular, what are the theoretical and practical limits in IQ if
you downsize to 6Mp?

If you can work in RAW then the 12MP cam will likely produce better prints simply because it likely uses better technology. However, in attempting to make a slightly better image mo' better, the image processing engine of the 12MP compact might do things to the image that you don't like.

The theoretical limit to sharpness is the diffraction limit. It is based on light and the lens. Two cameras with the same lens and same sensor size will have the same "real" resolution. The higher MP image is simply breaking up the same image into more pieces.
http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm

The OP merely speculated that greater resolution was the cheapest way
to giving a compact something to brag about.

No, nothing to brag about...they they've still have movie mode to brag about!

The OP suspect Graystar
thinks of IQ as an absolute and very closely related to "noise free".

It's an important part of IQ but sharpness, dynamic range, color accuracy, etc are also very important.

The only way a small-sensored camera will ever produce an image that
will rival a large-sensored camera is if it's a picture of white wall.

Why? It will still be noisier than a DSLR, and it will be very hard
to detect pixelization in the DSLR blowup...

If all the pixels are saturated (registering pure white) then there won't be any noise. Both images will simply be white boxes.