I've heard ___ is going to be X times faster than ___, where X is some ridiculous multiple like 4x, 10x, etc. too many times, and every time it turns out to be a total lie, or best case, a very specific situation in some highly niche case.  I think we can expect the next gen to be roughly the same incremental improvement we've seen from the last handful of recent generations - plus or minus 10 to 15% or so, the *70 card replaces the old *80 Ti, and the *60 card replaces the old *70, etc.