As suggested in another thread, let's share what our cameras can do at high ISO.
ISO 6400 jpeg on the RX100:

DSC01290 by Havoc315, on Flickr
Another ISO 6400 on the RX100:

Aug 31, 2012-68 by Havoc315, on Flickr
ISO 10,000 on the A99:

a99raw-50.jpg by Havoc315, on Flickr
ISO 12,800 on the A99 (I believe with Topaz DeNoise IIRC)

untitled-86-Edit.jpg by Havoc315, on Flickr
Compare that to the ugly 12,800 on the Sony A55:

birthday-75.jpg by Havoc315, on Flickr
Another 12,800 on the A99:

a99raw-5-Edit.jpg by Havoc315, on Flickr
One more 12,800 on the A99 with some Denoise..

untitled-155-Edit.jpg by Havoc315, on Flickr
6400 on the A99

untitled-138.jpg by Havoc315, on Flickr
6400 on the A99

untitled-143.jpg by Havoc315, on Flickr
ISO 6400 jpeg on the RX100:

DSC01290 by Havoc315, on Flickr
Another ISO 6400 on the RX100:

Aug 31, 2012-68 by Havoc315, on Flickr
ISO 10,000 on the A99:

a99raw-50.jpg by Havoc315, on Flickr
ISO 12,800 on the A99 (I believe with Topaz DeNoise IIRC)

untitled-86-Edit.jpg by Havoc315, on Flickr
Compare that to the ugly 12,800 on the Sony A55:

birthday-75.jpg by Havoc315, on Flickr
Another 12,800 on the A99:

a99raw-5-Edit.jpg by Havoc315, on Flickr
One more 12,800 on the A99 with some Denoise..

untitled-155-Edit.jpg by Havoc315, on Flickr
6400 on the A99

untitled-138.jpg by Havoc315, on Flickr
6400 on the A99

untitled-143.jpg by Havoc315, on Flickr