I haven't fully tested all the combinations regarding this issue yet, but I had some strange behavior by PS apparently when opening RAW images in 16bits. All works ok a part for a very annoying and weird pattern of fuzzy noisy colors in the grey background of the window which contains the photo. When I grab the bottom right corner of the window to make it larger all these patterns appear, mainly in the bottom of the window. They look very weird, like color noise very fine or purple fill color with black characters which don't make any sense. For all the rest the software seems to work just fine.
I'm running CS4 master collection on a new mac pro 4core.
Does anybody have the same problem? Does anybody know what it depends from and if there is a solution to get rid of it?