I've read in various places that the latest developer releases of 10.6 boots a 32-bit kernel on all non-Xserve machines by default and that a certain key-combination during boot (or hacking) is required to load the 64-bit kernel. I've also heard speculation that certain older x86's won't even be supported by the 64-bit kernel.
I've got an older MBP (MacBookPro1,1) and I'm already seriously peeved that OpenCL isn't going to support my Radeon X1600; this would only be icing on the cake.
So, is this all stuff and nonsense...baseless speculation? I admit I'm not even entirely sure why some x86's would be supported and not others. Can anyone help?