928 core clock on a 128bit bus with 768 cuda cores on reference is the 650ti vs 1020 with 1085 boost core clock with 640 cuda cores and a 128bit bus gtx 750ti is the comparison. Not a whole lot different considering (guess you could throw the reference 1gb vs 2gb as well) and the fact it completely takes it down a notch in every game benchmark I've seen shows that the pic improvements are pretty nominal. Even accounting for the high clock rate should not give something with less cores that much of a performance gap. The GTX 650ti boost has a 192bit bus and a core clock of 980 with boost to 1033 and with the extra memory and memory speed/bandwidth allows it to perform more on par with a 750ti however it still depends on the game as BF4 is better on 750ti while Metro for instance is better on the 650ti boost. Still in raw performance the 750ti is slightly ahead. Either way though if we include the way things are and the looks the GTX 880 even if it matches the core of a GTx 780ti will perform better. Still more of a wait and see game, but I still believe the 880 will be the next top dog.