Sudo systemsetup -setkernelbootarchitecture x86_64 Update: Apple has added a command line setting for enabling the 64-bit kernel. With 32-bit firmware, you cannot boot into 64-bit kernel it’s not possible.Ĭhecking whether 64-bit kernel is in use The configuration file approach for always booting into 64-bit PERMALINK See this Apple tech note for which machines can boot the 64-bit kernel You Mac might be a few years old and have 32-bit EFI firmware (the code that runs to boot the Mac). Does your Mac have 64-bit EFI firmware? PERMALINK You’ll want to verify if your software has any issues in 64-bit mode. Apple really can’t be faulted here, but you can make an intelligent choice for yourself. The reason not to boot into 64-bit mode is compatibility with software drivers of various kinds. But they won’t see full performance that way.
Your 64-bit programs (if any) will run fine on a 32-bit kernel, gaining the benefits of 64-bit-ness. Why not get a good chunk of that for about $25? Tests of photographic applications show that the gains of booting with the 64-bit kernel can be substantial, keeping in mind that a 30% gain via hardware often costs several thousand dollars more.
