I am using an EVGA 8800gt graphics card. I use a DVI to HDMI cable.
Refresh rate is 60hz.
Right now I am running 1360x768 resolution because when I set it to 1600x900 or 1920x1080 the image becomes very grainy. The TV sees the input as 1080p but it does not look as clean as 1360x768.
I use the TVs scaling. I tried turning it on and off with all resolutions but I cant make 1080p look good. I dont know too much about displays but it looks grainy and bleached out.
Im sure there is some information that you would need to answer my question. Ill provide it as best I can.
Wish I could help, I'm in the same boat. I'm running a 32" LG LCD that also supports 1080. It goes up to 1920x1080 as well but when I do, the image vibrates... lots of vertical noise. Not grainy like yours, more seizure inducing. I have a DVI-HDMI hookup as well. Funny thing is, before I got the high-def cord, I was using a basic DVI cord and could run 1440x900 and higher. The user manual for the TV said I could handle higher resolutions with the high-def cord, so I bought one... Now I can't even run what I used to without issues... Hell, 1440x900 doesn't even show up on the list of possible resolutions. I stuck with the DVI-HDMI because it gives a somewhat sharper image.