what's better gpu in :
(1)gt 840m 4gb DDR3+i7 4510u cashe6 ram 8
(2)gt740m 2gb DDR3+i7 cashe6 ram8
(3)amd 8850m 2gb DDR3+i7 4500u cash
(1)gt 840m 4gb DDR3+i7 4510u cashe6 ram 8
(2)gt740m 2gb DDR3+i7 cashe6 ram8
(3)amd 8850m 2gb DDR3+i7 4500u cash