In order to save time on explanations I just searched internet for “averaging noise” and found very nice article – exactly about the same subject where everything explained to full extent.http://www.cambridgeincolour.com/tutorials/image-averaging-noise.htm
So here is also typical photography application to for this - which I was referring in my posts.
Luckily it could be easily done with 1Dx using method I described above.
And now to scientific numbers)))
From article above : “ In general, magnitude of noise fluctuation drops by the square root of the number of images averaged, so you need to average 4 images in order to cut the magnitude in half”
So averaging 9 photos reduce noise fluctuations 3 times which is equivalent to 10*log(Sqrt(9)) = 4.7dB.
Look at DXOMark SNR curves for 1Dx and add 4.7 db to that at the flat left shoulder part at low ISOs and compare that to Nikon D800.
Does not look too bad after all that.
Not sure if D800 has the same multi-exposure mode.
If yes then it could get even more amazing results.
As for banding – I believe it could be easily removed as well:
I think but not 100% sure that banding is fixed specific pattern for each specific sensor .
If so it could be easily removed as well - just one calibration short with(-3EV) against dark gray surface using the same method. Save this calibration shot and then subtract this from the normal image in Photoshop - add calibration shot as a second layer above the image, invert this layer and adjust intensity, transparency and contrast for maximum banding removal.
I think all this technique could be easily incorporated in camera firmware for night shot mode.