Originally Posted by spookmag
Yes I have tried every hack or app there is. This app says that my system is 100% able to run 64bit kernel but is currently locked by apple to boot into 32bit mode. right now there are only eight model number macs that will boot into 64bit kernel. Supposedly they are going to unlock more of them via software updates. the next OS won't be 32bit at all so they better get to it otherwise my computer which is only 3 years old will not run 10.7
I also have an IMac 7,1 thus my interest in your issue. The link mentioned does not provide a solution, and states specifically that only iMac 8,1 and later are "enabled" for K64. That was the situation at Mac OS X 10.6.0 and that has not changed.
I am currently on Mac OS X 10.6.3 and have confirmed this via "About this Mac" > "More Info" > "Software" > 64-bit Kernel and Extensions
Basically, when you run on K32, you do not suffer any noticeable performance penalty. Applications that are either 32-bits or 64-bits will load on K32. If you have an iMac 7,1 you cannot install more than 4GB of RAM.
I don't know the exact technical reason why Apple decided to draw the "enabling" line as it did. Probably, the availability of drivers, or some hardware limitation despite the fact that you have a 64-bit EFI and a 64-bit processor.
How do you know that your computer will not run Mac OS X 10.7? I am guessing that it will. I would think Mac OS X 10.7 will support K32 and K64. I have not seen any information to the contrary.