CamCam107 :
Single monitor for gaming, other for other things
yes, so u yourself admitted that you will be using 1 monitor for gaming.
and that single monitor wont use 4gigs of vram.
but it will definitely use your 780gtx's 2gb for games even like crysis 30.(lol, if it gets released though)
dont think that- "WOOO I HAVE A 4GB GPU!!!! AND WILL OUTPERFORM ANYTHING!!!"
Definitely no.. it wont outperform a 780 in any way