Technically the 780TI. Having said that, a 970 is newer tech, it'll last longer and support new and upcoming games better. It sure as hell is way less power demanding, which means easy SLI. With some overclocking a 970 can eat the 780 ti, since it eats less power it also produces less heat, less heat equals less noise and longer lifespan. More Vram on the 970 also means better future compatibility.