Crossfire 7870 or new R9 280x?

Just can't make up my mind,  should I by another 7870 and go crossfire or by a new graphicscard ? 

My current pc http://pcpartpicker.com/user/PeachDK/saved/2EkC .(Hope the link works)

Got a XFX 7870 and a 850 watts powersupply, so crossfire shouldn't be a problem. But if I go crossfire I would't get to try AMDs mantel teknology.....  

Games I'm playing are Skyrim, Guildwars 2, Battlefield 3. Comming games I proabebly am going to play are battlefield 4 and Elderscrolls online. 

Reason for the upgrade is that I would like to have more headroom in games, so I do not need to set the grapfical settings down in order to get 60+ frames. 

Sorry for the bad spelling, (I just suck -_-). 

I would head for the r9 280x. Sell your current card and buy a r9 280x with a decent cooler (Asus, HIS, MSI TF).

mantle is on both

from what i know dual 7870s are a good bit more powerful than a 7970, downside is not all games make use of it along with all the problems dual gpu brings in, so a 7970 is more reliable if not as powerful

Agree  i´m personaly not a big fan of dual gpu setups, offcourse  if you play games that have a good optimization for it, then it will be all fine, but with games, that are not realy good optimized for it, are gonne be a pain in the ass..