[m42man]

It occurs to me I forgot to take into account the high pixel count of the D800. It has 3x the number of pixels compared to the Q; if it were to have the same number of pixels (which we need for a direct comparison in terms of equivalence), then noise improves by root 3, so it would have pretty much the same noise performance at ISO 3200 as the Q at ISO 100. As I mentioned earlier, an excess of pixels isn't a big deal (in fact it's very desirable), as you can reduce the pixel count in software, by downsampling. This has the same effect on noise as you would see by having the correct pixel count.

This implies the technologies used in the Q, K-5 and D800 have very similar noise performance, assuming equal pixel sizes.