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Is my new MBP booting by default on 32-bit or 64-bit kernel? (By size/Processor)

  • 15" i5 32-bit kernel

    Votes: 14 50.0%
  • 15" i5 64-bit kernel

    Votes: 3 10.7%
  • 15" i7 32-bit kernel

    Votes: 7 25.0%
  • 15" i7 64-bit kernel

    Votes: 4 14.3%
  • 17" i7 64-bit kernel

    Votes: 0 0.0%

  • Total voters
    28

djasterix

macrumors 6502a
Original poster
Apr 10, 2010
625
1
Paradise City
Does anyone knows why my new 15" i5 MBP is running 32-bit kernel instead of 64-bit?, is it disabled for any reason? thanks
 

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That's totally normal. More details here: http://arstechnica.com/apple/reviews/2009/08/mac-os-x-10-6.ars/5

64 bit kernel and extensions is only enabled by default on Xserve servers. None of the desktop-class machines boot with a 64 bit kernel by default. This doesn't prevent you from running 64 bit apps, it's just the kernel that is affected.

Ok, thanks for that but, isn't a 64-bit system more efficient? Then what's the reason to have a 64-bit processor, a 64-bit OS and running it on 32-bit?, I don't get that...
 
That's totally normal. More details here: http://arstechnica.com/apple/reviews/2009/08/mac-os-x-10-6.ars/5

64 bit kernel and extensions is only enabled by default on Xserve servers. None of the desktop-class machines boot with a 64 bit kernel by default. This doesn't prevent you from running 64 bit apps, it's just the kernel that is affected.

Oddly enough, my 17" i7 boots with a 64-bit kernel for some reason and I never told it to...
 
Well, I don't get it, as there are some 15" i5's booting on 64-bit by factory default, and some 17" i7's booting on 32-bit...

BTW, i'm running on 64-bit mode to test it and so far everything is fine, just a loooong boot time...
 
Ok, thanks for that but, isn't a 64-bit system more efficient? Then what's the reason to have a 64-bit processor, a 64-bit OS and running it on 32-bit?, I don't get that...

The reason the kernel is still running 32-bit in most cases is to increase compatibility with 32-bit programs. Not all develoeprs have upgraded their software for 64-bit support, and so there's no telling really how they'll run. Some apps will work just fine, while others won't run reliably (or at all) on a pure 64-bit environment.

Remember the hell Windows Vista users had when they upgraded to 64-bit? Your MacBook Pro is supposed to boot in 32-bit by default to avoid that. You can see what's still running in 32-bit mode on your mac by checking System Monitor:

zSPCM.png

(Note: this screenshot is from my Mac Mini, not my MBP, but you get the idea.)


Anything that doesn't have "(64-bit)" in the "kind" field is running as a 32-bit app.

When you have software that has 64-bit support, it runs in that mode and gets most of the benefits. Otherwise, it runs in 32-bit mode.

Now, WHY some i5s and i7s are apparently rolling off the line set to to boot 64-bit by default, I'm not sure. The company line from Apple is that only the Xserve boots in 64-bit by default.

On the other hand, now I wonder if we can tie this weirdness to the freezing issue some people are having. Are those with freezing issues booting in a 64-bit kernel?
 
On the other hand, now I wonder if we can tie this weirdness to the freezing issue some people are having. Are those with freezing issues booting in a 64-bit kernel?

That's a good point, so lets see if people booting on 64-bit kernel are experiencing freezing. I've been running on 32-bit and never had a problem, now I'm running on 64-bit to test it.

One maybe silly question, if I'm running 64-bit, 32-bit apps will not run?, or the problem is that you don't know how they will behave?
 
Heard on another thread that Paralells won't run on 64-bit. I'm running windows 7 via Fusion 3 without a problem...
MacFUSE is the one application that completely prevents me from booting my MBP in 64-bit mode. I've been waiting for a 64-bit kernel module for a while and it looks like I'll be waiting a while longer. 32-bit mode is comparable in speed to 64-bit mode in almost every respect for the programs I use, but virtualization was a little faster in 64-bit.
 
One maybe silly question, if I'm running 64-bit, 32-bit apps will not run?, or the problem is that you don't know how they will behave?

Some apps will work fine, others will behave erratically, and others might not run at all. It's a mixed bag.
 
Ok, thanks for that but, isn't a 64-bit system more efficient? Then what's the reason to have a 64-bit processor, a 64-bit OS and running it on 32-bit?, I don't get that...

Whether your kernel is 32 bit or 64 bit matters very, very little. 64 bit applications work absolutely fine on a 32 bit kernel.

The reason the kernel is still running 32-bit in most cases is to increase compatibility with 32-bit programs. Not all develoeprs have upgraded their software for 64-bit support, and so there's no telling really how they'll run. Some apps will work just fine, while others won't run reliably (or at all) on a pure 64-bit environment.?

That's nonsense. Applications don't even know whether the kernel is 32 bit or 64 bit. It's only _drivers_ that care. A 32 bit application will run in 32 bit, whether the kernel is 32 or 64 bit. A 64 bit application will run in 64 bit as long as you have a 64 bit processor, whether the kernel is 32 or 64 bit.
 
That's nonsense. Applications don't even know whether the kernel is 32 bit or 64 bit. It's only _drivers_ that care. A 32 bit application will run in 32 bit, whether the kernel is 32 or 64 bit. A 64 bit application will run in 64 bit as long as you have a 64 bit processor, whether the kernel is 32 or 64 bit.

So we're fine on 32-bit kernel and all 64-bit apps will work on 64-bit, it's not limitating?
 
Ok, 4 days running on 64-bit and almost all ok, long boot only first time, now boot time is normal, and a little faster than 32-bit. Only bug encountred is remote control not working properly with power point, but i'ts working great with keynote, itunes, quicktime x and front row.
 
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