Thanks all for your replies. But still the problem still persists
1) The 1-1 tv option
The HDTV was already set for "Full Pixels" so that is not an issue.
2) MDP
I bought an adapter from the local authorised reseller with the capability to pass audio as well (it is not a straight cable). However when I connected the HDTV, with the adaptor and an HDMI cable, and set it at 50Hz or 60Hz I started seeing White 1 pixel tick dots dancing around on the screen. The cause of this trouble could be the cable, the adaptor or the graphics card. When I connected the HDTV with the DVI to HDMI cable this problem ceased to exist.
3) Windows
When I set up Windows the only problem I had was with the overscan. I downloaded the catalyst driver and the problem was solved. Under Windows the text is smooth and the colours are correct.
4) Mac OS X
In setting -> display all I get setting are for resolution, refresh rate (24Hz, 50Hz, 60Hz), over and under scanning and rotation.
For resolution I don't get 1920x1080 but just 1080p and 1080i
I am not able to set the colour like on the iMac from thousands to millions and the like.
Under the colour tab I can set the different profiles however when ever I choose a profile and restart the setting is lost. To enable the profile I have to enter the system preferences choose display choose colour tab and the setting is applied. Another thing when I connected the Sony TV with the DVI cable I got another colour profile name Sony xv.
I am annoyed that Windows has video compensations when connecting to an HDTV and that Mac OS X doesn't. The text under Mac OS X is nearly unreadable and the colours aren't that good.