970 vs. 770

Solution
The GTX 970 runs at about 15 fps more than the 770 but keep in mind that the GTX 970 has 3.5gb of VRam though that won't be a problem in 1080p gaming


I think hes saying that he currently has two 770 classified cards in SLI. Hes looking to upgrade to one GTX 970. But I'm really not sure.
 
Just to clarify, there's a misconception that 1080p doesn't use more video memory than the 970 has in it's first, faster partition. That's incorrect in many cases. Shadow of Mordor for one with everything maxed out can use almost 5GB. GTA V uses just over 4GB with the same stipulations. All of these instances can be avoided by disabling AA
 


The dual classified is a evga model with dual fans, not dual gpu chips.

To answer the question, I would not advise such a upgrade, The difference in performance will be minimal and only detected by a synthetic benchmark and not by gameplay.

Even a GTX980 would not be a game changer.

Look for a GTX980ti, it is as good as it gets for gaming today
 


So are you saying that for example in Witcher 3 or Middle-earth: Shadow of Mordor the two GPUs would perform roughly the same?