That shouldn't really matter too much. The boards themselves are light as hell, when you pick up an amp most of the wieght you feel is the heatsink. So, they may have just advanced their heat-dissipation design and don't need to use such a huge, heavy heatsink.i was thinken bout buying the 15:0:1 or what ever it was..the 1500 watt one....i swear that thing weighed like 2 lbs....i did not get it....