Official Mac OS X 10.6 Snow Leopard Thread & FAQ - Page 26

ElDiabloConCaca · #**201** October 10th, 2009, 12:42 AM

Quote:

Originally Posted by lighthart2000

What I want to know ... is why Apple has hobbled my flagship product (Mac Pro, Quad Xeon, 8 gig memory) with a 32bit EFI. Imagine my surprise when SL came out and I don't have 64bit kernel support!

I use almost all the apps listed in the following performance review, and hence am missing out on some serious performance increases!

Even though your kernel runs in 32-bit mode, applications (if so written) will run in all of 64-bit glory.

That means that those applications will run exactly the same whether you boot into a 32-bit kernel or a 64-bit kernel.

You are not missing out on any kind of real or perceived "performance boost" by running a 32-bit kernel. Any 64-bit applications will run in 64-bit space, with all the same 64-bit performance increases, the same as they would on a computer that boots into a 64-bit kernel.

Just FYI, the only Apple computer that boots into a 64-bit kernel is the XServe.

To sum it up, you're not missing out on anything. You can address all your RAM in your computer, and OS X doesn't run any faster in 64-bit mode than it does in 32-bit mode.

The amount of "bits" of a kernel has extremely little to do with "speed."

Doctor X · #**202** October 10th, 2009, 12:47 AM

. . . yeah but mine goes to 11. . . .

--J.D.

lighthart2000 · #**203** October 13th, 2009, 04:36 PM

Quote:

Originally Posted by ElDiabloConCaca

Even though your kernel runs in 32-bit mode, applications (if so written) will run in all of 64-bit glory.

That means that those applications will run exactly the same whether you boot into a 32-bit kernel or a 64-bit kernel.

You are not missing out on any kind of real or perceived "performance boost" by running a 32-bit kernel. Any 64-bit applications will run in 64-bit space, with all the same 64-bit performance increases, the same as they would on a computer that boots into a 64-bit kernel.

Just FYI, the only Apple computer that boots into a 64-bit kernel is the XServe.

To sum it up, you're not missing out on anything. You can address all your RAM in your computer, and OS X doesn't run any faster in 64-bit mode than it does in 32-bit mode.

The amount of "bits" of a kernel has extremely little to do with "speed."

El,
Can you explain why the performance review shows an increase in performance between 32bit SL and 64Bit SL in the apps that I use almost every day? (Real world stuff) I'm sure bigger and more files would broaden the gap:

And holding down the 6&4 when booting will give you the 64bit kernel.. on those platforms that support it -- which the later model mac Pros do!

ElDiabloConCaca · #**204** October 13th, 2009, 04:48 PM

Your linked graph shows a ~3% performance increase.

Which tests show a 30% increase in performance?

And what is "performance?" Speed? Memory footprint? A single Photoshop filter?

And are these tests testing Mac OS X booted into a 32-bit kernel vs. a 64-bit kernel, or Lightroom booted into 32-bit mode vs. 64-bit mode (because it's possible to run a 64-bit Lightroom in a 32-bit kernel)?

lighthart2000 · #**205** October 14th, 2009, 10:39 AM

Quote:

Originally Posted by ElDiabloConCaca

Your linked graph shows a ~3% performance increase.

Which tests show a 30% increase in performance?

And what is "performance?" Speed? Memory footprint? A single Photoshop filter?

And are these tests testing Mac OS X booted into a 32-bit kernel vs. a 64-bit kernel, or Lightroom booted into 32-bit mode vs. 64-bit mode (because it's possible to run a 64-bit Lightroom in a 32-bit kernel)?

El,
I have to admit the 30% increase is between Leopard (32bit kernel and app) and the 64bit kernel and app in SL. As you pointed out there is only about a 3-5% between the 32bit and 64bit kernels. And the graph is showing both 32bit and 64bit apps(green and blue respectively) and SL 32 & 64bit. Notice this is only loading 128 files (a very small catalog in LR), most of my imports would be on the order of 2-3000. My assumption is that the gap would widen as this would "stress" the kernel more. And performance as I would perceive it is all of the above.. how fast I can load images, how fast I can batch change, how long a given filter takes to apply... my guess is the kernel would only come into play in the load (as I'm given to understand the kernel will get involved in any i/o intensive operation disk -> graphics card/memory -> back to disk).

Thanks for your input! I guess I am still rankled by the "perception" of being hobbled, even if its only 3-5%. Again remember the newer Mac Pros are 64bit kernel capable.. I am really thinking about my early adopter status...

ElDiabloConCaca · #**206** October 14th, 2009, 10:57 AM

One of the reasons that all Apple "consumer" machines (barring the XServe) boot into a 32-bit kernel is that all kernel-level drivers must be of the same architecture and bit-width as the kernel.

OS X is UNIX, and UNIX has a ton of drivers (especially with a microkernel like OS X uses), and if you boot into a 64-bit kernel, then all those drivers must also be 64-bit. For the consumer use of OS X, not all kernel-level drivers (or "kexts") have been ported/recompiled as 64-bit drivers, so in order for Apple to offer the most compatibility, they defaulted to a 32-bit kernel.

I understand the concern, though -- even if it seems artificial. If the computer can do 64-bits, then it should do 64-bits... the only problem is that the drivers for said 64-bit computer may not all be 64-bit.

Still, applications can and will run in 64-bit space if and when they can. Mathematica, Maple, etc., all run in 64-bit glory and get the same 64-bit performance increases whether the kernel is booted in 32-bit or 64-bit mode -- there is absolutely no difference in the behavior and speed of the app itself.

lighthart2000 · #**207** October 14th, 2009, 11:52 AM

Ok, now we are getting to some meat (smile). I have been through the issue on Windows with 32 and 64 bit drivers and applications. One of the reasons this (all) is key is that I believe 64bit is slowly "coming into it's own" and now we are "feeling the pinch" as both platforms struggle with implementation. I have an AMD 64bit that I have both 32 and 64 bit Windows (xp, vista, and windows 7 loaded). 64bit app support is lagging in the windows world, so Apple is "in parity".

I guess what I am saying is in my excitement I bought into the "marketing hype" of SL as a "true" 64bit platform, when in *complete* technical reality we (consumers) are not "there yet". We are "sorta there" with the 64bit apps running in 32bit kernel... and I understand what you are saying relative to the kexts.... another reason it took so long for Windoz 64 to come out in all it's dubious glory was the drivers.

So now with Windows 7 launching in all its 64bit goodness, was Apples response SL? And will that be enough? Time will tell. I look forward to the next OS X release with full 64bit support (and yes.. on my Mac Pro 1,1).

lighthart2000 · #**208** October 14th, 2009, 11:57 AM

Oh I didn't see any response to my last query? Anyone see a significant "snappiness" increase in SL clean install over the upgrade? I did both and the SL clean install on my MBP feels much "snappier" (seems to boot faster, windows open faster, just all around "faster") And sorry.. no "benchmarks" to prove this...
(I did install a 500gig 7200 rpm HD in my MBP but I really don' think that is the reason).