I have tried the 64bit ver of PI3 which I download from Wondertouch. It did indeed lose its activation. I have since returned to the standard 32 bit Windows for now since other programs like my dialup modem software, Vegas 6.0, Heroglyph and other animation apps that I need don't work either.
Just in case your asking my hardware is 64 bit ready as well as my Windows OS. I think we so on the cutting edge that we are getting hurt :)