To the 780? I'd say the 280x is almost there, and the 290 is a bit more, but the 290 has been ridiculously inflated by the companies selling them because of bitmining. At the rate of inflation, and the fact that the price probably won't die back down to affordability, get a 780 instead of a 290.
And, for the 760? 270x and up are better, and the 260x might be a tiny bit weaker.
And, for the 760? 270x and up are better, and the 260x might be a tiny bit weaker.
in a perfect world we would all be piles of sand with no ability to form coherent bodies of body