sudden fps drop in all games after connecting with TV

same resolutions ?? a screen at a lower res will be faster the one at a higher resolution ? if I go from 800x600 to 1920x 1080 there will be a big hit ?

between my 1080 60hz monitor and my 2 hdtv's at 1080 60hz its all the same plays the same ?? may depend on how well your hdtv takes to pc use some do great and some just suck if can do pc use at all