With the bore diameter of a 70 cc saw and the stroke of a 50 cc saw, I dont think the weight savings on the 564 is all that impressive: 12.8 lbs. It still costs as much as a 70 cc saw.
They're marketing this as some sort of pinnacle achievement where this micro-penis-short-stroke architecture has made such a big difference in weight savings.
On the other end of the 60 cc bore/stroke ratio: an echo 590 weighs 13 lbs 5 oz. Its exactly the opposite: A bore diameter similar to a stihl ms 261 and a stroke similar to a husqvarna 181.