DX is updated, this TV can go up to 1080i, i used to use on my HD4670 when I needed more desktop space and I also use it for a time on ps3 before i missed the higher refresh rate on 720p.
it can handle 1080i, other words 1920*1080@ max of 30hz, 1366*768 is at 60hz, another reason why I prefer it.
I am pretty sure it is because I have to manually insert the edid data into the nividia driver before it installs and i think the edid data is slightly off, which it can be in some flat screens, I did not have to do this on my HD4670 hence why I had no problem.
Apparently this is a very common driver problem with nividia which they refuse to recognise, this is the guide i followed to get the colours and text correct: Colors are washed out/fuzzy with nVidia driver - NVIDIA Forums - Page 2
Basically I think I am looking for some kind registry tweak to allow it to report the correct resolution so I dont have to manually add it in using ps or nvidia cp or i need to write my own EDID data and input it into the nv_disp file, and that could take a while for a problem that only causes issues in dx9 games and is only noticeable you look real close
This appears to be a relatively unique problem but I like challenges, most people either just wouldn't care or prob wont notice it during gameplay.