Cru 3d Mode Overclock. 1280x720p 90hz

Hi@all,

Please help me. I'm trying for a few days to oc my TV.
Now i discovered something. If i enable in Windows Display settings "enable 3d for all Supported screen" it adds to nvidia Resulutions two new ones. 1920x1080 and 1280x720p Now i can Overclock upto 90hz.

But this 90hz is almost as 60hz is regarding bluer. Just a Little better.

Could anyone explain to me why i cant Overclock in 2d ? Only After enable 3d Mode oc to 90hz ? Its Not real 3d TV dectects 3d and ask If it should be enabled If Hit ok its still 2d.

Thank you all