igmarn :
vortical :
A single more powerful GPU will be much less of a headache and is always preferred. Take it from someone who has an Xfire (2x 7870's), that there will be times where you will spend an hour trying to get a game to run well on xfire only to run it on a single gpu anyway.
I dont know alot about computers but it for pure performance, i would find it more logic that 2 are better than one. So you say i should avoid xfire of sli and buy a single card.
xfire 270x is a little bit more expensive than a gtx 770 but a 770 should be better?
For a single card which one is the best:
R9 270X
GTX 760
R9 280X
GTX 770
the 280x and the gtx
770 are about equally good, with the 280x getting better at high resolutions like 1440p.
In general 2 cards will be more powerful, however there will be a lot of errors and bugs you will get because you have two. For me and most , the added effort of dealing with all the errors isnt worth the extra power.