http://www.dxomark.com/Cameras/Compare/Side-by-side/Pentax-K-3-versus-Pentax-K-5-IIs-versus-Pentax-K5___914_830_676
Despite the high pixel count multiplying factor, the K-3 still loses the game against the old K-5, and the other K-5II variants as well.
Update (11-30): Shouldn't we compare the K-3 to the recent hottest FF like A7R and D610, and see what happens?! :-o
http://www.dxomark.com/Cameras/Compare/Side-by-side/Sony-A7R-versus-Pentax-K-3-versus-Nikon-D610___917_914_915