well dude, I probably almost certainly wouldnt have noticed the banding if you hadn't pointed it out. If you check out the colour banding, the change in colours isnt drastic at all, maybe one or two points at most, but because it's spread out, it can be noticed. This isn't because you aren't getting the colours that are supposed to be inbetween those colour values, to my eyes it looks like there isn't any colour between those values. Its like a gradient. from afar it looks fine, but zoom in and you can see what looks to be banding. It's just the colours transforming from one to the next. bottom line, I can't for sure tell you what's going on and why its happening. What i said above is whqt I believe to be the culprit, but I'm just some canuck. Bringing up the parhelia was not meant to be a solution by any means, it was just what came to mind when i saw your problem. check out the info on the site, it might prove enlightening as to why it's happening. Very few video cards are 10-bit per channel, and not a single ATI/Nvidia chip that i know of is. Maybe some 3D Labs and whatnot perhaps... as for changing your image to 30-bit, get a matrox parhelia that is capable of displaying imagery at 30-bit, install the pluging for photoshop that comes with the card, and then you can see. I won't though cause i use a Radeon.