It looks like some 64-bit Intel Macs won't be able to use Snow Leopard's 64-bit features, because their EFI firmware is 32-bit.

Even if you have a 64-bit enabled EFI, it seems only XServes will use it by default, all other machines will require the user to press the 6 and 4 keys whilst booting!

The list of what is and isn't 64-bit is not very clear from the lists from Apple, but if you want to test, open a Terminal window and copy and paste the following command in :



This should return either "EFI32" or "EFI64". If it returns EFI64, then your machine should be capable of running the 64-bit version of Snow Leopard (if you press 6 and 4 during boot), otherwise you are stuck with 32-bit mode.

This seems to be artificial, as the 32-bit EFI is capable or booting the 64-bit kernel. Even worse, MacBooks (without the Pro in the name) won't be able to use 64-bit, even if they are 64-bit enabled, because of an artificial restriction by Apple (I assume C2D minis would suffer the same fate).

Astonishingly, pre January 2008 Mac Pros won't be able to use 64-bit mode either! That can't be right, can it?

The non-automatic selection of 64-bit mode is on what is rumoured to be the Golden Master, although it has not been confirmed by Apple that this is the final release. So there is still hope that this situation will be rectified, before SL is finally released. It seems unbelievable that the old Pro machines, with dual 64-bit processors won't be able to run the 64-bit OS, that could have serious repurcussions from professional users... Which is why I will take it with a pinch of salt, before I see the final release.

Personally, I would hope that 64-bit capable machines get a Preferences panel to allow them to switch between 32-bit and 64-bit modes, or the use can select which at install time...

ZDNet Source clicky

So, a firmware update is out of the question during the install?

My MacBook is from 2006 or 2007. I assume it can't run the 64bit mode.

I'll run that command when I get home.

I seem to be stuck with 32-bit mode. Then it's a 2007 MBP, so what would I expect?

C'est la vie.

Well that sucks then.

If this is the case in the final release, I wonder why it is...My initial thoughts are that parts of the code are unstable running in 64-bit mode, so rather than release a buggy system on time or pushing back the deadline after promising an Autum release, they can release a stable system and then add firmware updates along with the incremental updates to enable more and more parts of the system to be 64-bit as they become more stable?

Or does that sound to obvious and Apple are actually just playing with everyone?

In which case, why do the servers boot automatically into 64-bit mode? The servers should be running in the most stable environment, not the least stable!

I would presume that Apple needs certain parts or a certain amount of the system to be 64-bit enabled to advertise it as such, and seeing as Apple time and time again say how OS X is so stable, I would guess they would have made any code that is 64-bit enabled by default rock solid.

We are talking about the Kernel and KEXTS here. These will load in the 32-bit versions on normal Macs and in 64-bit versions on the Servers and those compatible Macs, where people press 6 and 4 at boot time, but the number of Macs which don't seem to be compatible seems fairly high!

The reported situation doesn't make any sense at all. Unless they want to throw out their 64-bit hardware and buy new 64-bit hardware, in order to run SL in 64-bit mode...

My MBP seems to have the 64-bit version. But then it is brand new.

Same here, hurah! My 3.5 year old Toshiba laptop will also run a 64bit OS (Vista SP3 and Ubuntu) just fine. I guess you get what you pay for....oh...hang on....

I don't find OSX that stable as it is. Applications are quite prone to freezing and you have to perform some obscure finger kung-fu (cmd, alt and some key I haven't found yet) to try and get it to quit. If you do get the force quit box up, it is still touch and go whether they will quit when you tell them to. I've had hold the power button to shut down a few times now.

According to Microsoft and the makers of Ubuntu, you are running a 64-bit OS, according to Apple you'll be running a 64-bit OS. In the world of marketing, what constitutes as a 64-bit OS?
Indeed, I've not read the article, but how credable it it?



I don't get many freezes, but when I do I've found that they don't bring the system down and can often be left for a few minutes to sort themselves out...

That covers about 99.9% of the freezes I have with OS X and Windows... I can't remember the last time a freeze brought either Windows or OS X to its knees.

Some dodgy RAM in my old PC used to blue screen it on a regular basis, until I swapped it out, other than that, I haven't seen either crash for a couple of years.

The current OS X is a mix of 32-bit and 64-bit extensions, but the Kernel is 32-bit only. SL should bring 64-bit throughout, but it looks a little selective and ham fisted in the latest build, which is rumoured to be the Gold Master...

As I said, I think I'll wait and see what finally comes around, but the current situation is a little disappointing.

Unibody MacBook Pro on release late 08

Not surprisingly, EFI32 - October 2006, 1st Generation 24" iMac... It can only use a maximum of 3GB anyway, so no real reason for 64-bit on the machine.