iMac7,1 64bit?

Why do you need to boot into 64-bit? Running >8GB of ram and over 2000 processes?

Nope. My MacBook Pro can't use more than 3 GB of RAM, but that is not affected by the kernel process. It is the applications that must be 64-bit to access the greater address space, not the kernel.

Take a look at [this article|http://www.computerworld.com/s/article/9137229/What s_the_real_deal_with_64_bit_computing_in_Snow_Leopard?taxonomyId=89&pageNumber=1]. It's not the whole story, but it does provide a good bit of it.

No perceived difference to most users, perhaps. It's evolutionary that everything will be 64bit soon. Then we can argue over 64bit vs. 128bit. 🙂

There is a big misconception between booting the 64-bit kernel - possible on some systems, but disabled by default on all but xserve - and 'running 64-bit'. Any Mac with a 64 bit CPU (regardless of the EFI) will run 64-bit as apps can switch into long more at any time - and do.

Apple was wise not to make 64-bit kernel ⚠ the default - it would have broken all the kernel extension that are 32-bit only, and which 3rd parties and developers still need to bring up to speed. Logitech LCC? no work in 64 bit kernel.

Remember, the 32-bit kernel can and does run 64-bit applications fine. It CAN use 64-bit memory addressing. There is no 'boot switch' from 32 to 64. What people are doing / talking about it mere forcing OS X to book the 64-bit KERNEL (and hence ONLY boot 64-bit extensions).

In other words; you are fine! 🙂

Cheers,
Dan

Have a look at Activity Monitor. It now displays which processes are 64 bit.

charlie

I also have the iMac7,1. I understand that I am still getting most of the benefits of a 64bit OS even though the kernel is booting in 32 bit mode, but it seems strange that this model cannot be forced to load the 64 bit kernel, while the iMac8,1 and iMac9,1 can. Is it some hardware limitation outside of the CPU? Others have mentioned that the EMI actually makes the decision to boot 32 bit on this model, and disregards the override. Do you think this is temporary, or is there a limitation to this model that the iMac8,1 doesn't have? I mean, the 7,1 has the core 2 duo cpu and the 64 bit EMI, so this is strange.

I also have a 7,1 iMac and cannot boot in 64-bit kernel mode. Is Apple going to issue a firmware update to allow it?