I have a 780 GHZ and it rocks. i was able to overclock stable to 1215/7208 mhz temps are under 65 deg on auto fans. it will out perform a reference 780 ti no problems. The amp or ghz are about the same. i couldn't justify the extra money for the ti. at 2560x1440 with ultra preset and 4xmsaa im getting between 70-90 fps on bf4 with dips into the mid 50's under extreme scenario's
an oc'd ti will be where it leaves the non ti behind. i would be more concerned with ram as im hitting between 2.4 to 2.8 on the above settings in bf4. so im worried where it will be with future games