according to this article

http://www.macworld.com/article/142379/2009/08/snow_leopard_64_bit.html

Snow Leopard is fully capable of running 64bit apps, but the OS uses a 32bit kernel because current hw does not need a 64bit kernel. part of it might as well be true, but I don't currently really care: the important part is the full 64bit capability. hence, I will be able to play n64 at 50% of speed with no frameskip :P

back to the autodetect point, there is no problem if I have to add a PTR64=1, but I would suggest to update the original instructions with a paragraph about Snow Leopard 32bit users because the speed gain with a 64bit compile might be appreciated wink