why does a 780 only get like 7 fps more than 770

Solution
The GTX 780 is also clocked significantly lower than a GTX 770 and needs to devote additional cooling overhead to the compute specific resources inherent to the GK110.
Overall, the GTX 780 is approx. 15% faster than a GTX 770.
Assuming your GTX 770 was averaging 47 FPS in whatever you are benchmarking, this 15% increase would equate to a 7 FPS boost.

perfrel.gif
The GTX 780 is also clocked significantly lower than a GTX 770 and needs to devote additional cooling overhead to the compute specific resources inherent to the GK110.
Overall, the GTX 780 is approx. 15% faster than a GTX 770.
Assuming your GTX 770 was averaging 47 FPS in whatever you are benchmarking, this 15% increase would equate to a 7 FPS boost.

perfrel.gif
 
Solution