Need some help with upgrades

Hi there. Current specs are :

  • 3930k @ 4.2 GHz
  • GTx680 FTW 4GB GDDR5 
  • 16GB Mushkin Blackline Enhanced Ridgeback 2133MHz Dual
  • Corsair H60 WaterCooler (Replacement for broken 110)
  • H850x PSU
  • 1TB HDD
  • 256mb SSD in the mail at the moment :D


Question for you guys, is should I upgrade my graphics card as a whole to a new card like the 290x for mantle awesomeness, or slap another gtx680 in sli ?


Which would be the best for performance versus price?


Thanks :D And if Logan doesn't release the new album soon Im going to release bears into his mountain home. 

another 680 is going to be cheaper and dual 680's could out perform a single 290x

that 850 watt psu should handle the other card fine

Thanks man :D