image peculiarities

So I have my images all buttoned down (or so I think) and I see some variances between the clients.. I have 16 computers booting one volatile image and it seems only 1/2 of them get the NTP info I hard coded into the image master.. Also. I set the power option (labeled as WSM Performance in Control Panel> Power Options) to NOT turn the monitor off after 20 minutes (seemed like a bad option in a Public Library) and they all turn off.. If anyone has any tips on applying settings uniformly I am all ears..