I’ve taken the plunge and installed Snow Leopard (aka Mac OS X 10.6) and was pretty psyched about the fact that it’s a 64-bit operating system, until my brother said “yeah, but I bet you’re still running in 32-bit mode”. How can I tell if my Snow Leopard computer is now running in 32-bit “compatibility” mode or as a true 64-bit operating system?
Before we go further, realize that the majority — if not the vast majority — of people running Mac OS X 10.6 Snow Leopard are running in 32-bit mode. In a lot of ways, I think that the 64-bit capability of the operating system is there for future growth of the platform, not because your iMac or PowerBook can handle it (or needs it, for that matter).
For an operating system that Apple has said is all about fixes and tweaks, there’s actually rather a lot of new stuff that shows up, and a lot of code has been rewritten and enhanced without much fanfare.
One example that’ll be critical for our needs is the Activity Monitor, which you can find in “Applications” –> “Utilities”. Launch it and you’ll see something like this:
Notice the “Kind” column. As you can see, some programs run in 64-bit mode, while others run in 32-bit mode, approximately 50/50 on my computer. Third party apps, like Adobe Air (which runs Seesmic Desktop) and Microsoft Entourage run as 32-bit applications, no surprise there. But if you look closely, you’ll see that iTunes is also still a 32-bit application. Hmmm… I expect that to change fairly soon!
This doesn’t show you whether you’re running in 32-bit or 64-bit mode, though, so to ascertain that you have to go through a slightly different hop… click on the “Apple” menu and choose “About This Mac” then click on the “More Info…” button. This will launch “System Profiler” and if you look down the left side you’ll see the major categories of “Hardware”, “Network” and “Software”. Click on “Software” and if you’re running in 32-bit mode, you’ll see this:
See that line “64 bit Kernel and Extensions”? The value “no” means that you’re not running in 64-bit mode.
Now, try rebooting and forcing 64-bit mode by holding down the “6” and the “4” key during boot. There’s not much you’ll see different when you’re running this way, but if you navigate to the same area in “System Profiler”, you’ll now see this:
You can also tell if individual apps are 64-bit capable by using the good ole’ “Get Info” command. A 32-bit program that can’t run in 64-bit mode will look like this:
By contrast, a 64-bit friendly app shows this:
The key is near the bottom: “Open in 32-bit Mode”.
One final thing to show you: If you do boot into 64-bit mode, go back into Activity Monitor and you’ll see a funny thing:
That’s right, even in 64-bit mode, you’ll find that much of your system is running in 32-bit mode anyway.
Ah well, now you know. Should you care? Probably not. Apple has done a splendid job of hiding this level of complexity from the user, so if your system works then you’re good! Oh, and don’t forget, I have lots of Snow Leopard help here on the site too.
Not sure what to advise, Zzzhuh. Check this out, though: tp://cache.vzw.com/multimedia/mim/usb760_pp/usb760_pp.pdf
Verizon told me that the no-Contract Mobile Broadband Model USB760 will work if my Macbook is 32 bit, but will have difficulty if my Macbook is 64 bit.
Do you think it would work or have difficulty?
Hey! I got a question. When i open Aperture a message appears witch tell me to start Aperture in 32 bitmode for, otherwise i can not use the Color efex plugin..
But! i have tried to change to 32bit mode(applications – Aperture – Get info – “Open with 32bit mode” box), but without success. When i after that relaunch Aperture this message appears again, “change to 32 bit mode”.
I use SL BTW.
What am i doing wrong?
please help!
Thanks, Wandile!
Joshua, I can’t imagine a reason why you would need to work in one mode or the other as long as you’re not hitting compatibility issues with individual applications along the way.
Hey Dave,
Very informative, answered my question exactly. Next question, as a web designer (design in Adobe, code, etc.) does it really matter in my day to day work whether I’m in 64 bit mode or 32?
hi, how do i install 32 bit drivers on my OS 10.6, cuz now i can not install it says not compatible. what shall i do? how can i switch 64bit to 32 default OS? i tried that holding down 3 and 2 buttons when computer is booting up. but still can not install drivers.
This is the best help article I have seen in a while. Gave me exactly what I needed. Dave, you rock!
Good article. My small problem I could not switch to 64 even after rebooting and holding down 64. Is it bec of my hardware? 1.83 Intel Core Duo?
Splendid question, jimthing. When Win7 and VMWare for Snow Leopard (Sneo? Snepord? Snoleo?) both come out, then we’ll know what’s going on. 🙂
Same question, different operating system; Windows 7, to be precise.
Just got Snow Leo (nice under the hood benefits, but on top ones mostly hidden-to-surprise later), but was considering using VM Ware to get Win 7 on my 17″ Macbook Pro.
Is W7 64-bit, and does it integrate well on a Mac using VM/Parallels?
GREAT GREAT JOB – that explained me a lot about Snow Leopard 64-bit system. Thanx a lot!