OSD has Overscan or Full under Aspect Control. In between that is 4:3 but it skips over that. I do not see Overscan in CCC. I see no difference in Full or Overscan when I switch.
ETA: I have not had an ATI card since 1998! Unfamiliar with how to get to the DTV portion of the CCC, now I found it and moved overscaling to 0. Much better.
Thanks for pointing me in the right direction.