2 single graphic adapters vs one duel graphic adapter?

I want the truth is a duel gpu card better in any other area for computing then to place on a mainboard that has only 1 pci express slot or two? If it proforms better in some games then 2 separate adapters linked together then what games. Finally is the price of a duel gpu graphic adapter being exactly twice the... show more I want the truth is a duel gpu card better in any other area for computing then to place on a mainboard that has only 1 pci express slot or two? If it proforms better in some games then 2 separate adapters linked together then what games.
Finally is the price of a duel gpu graphic adapter being exactly twice the price of a single though the single is in fact at least 20 percent faster then the duel when two singles are being used; only twice as much because it can be used on a single pci express slot mainboard and the companies that produce would like to finally just capitalize to capitalize? And charge regular single graphic adapter price times 2.
3 answers 3