64-bit Snow Leopard
flarosa
I have an early 2009 iMac, with 4GB. Recently I tried booting it up in
64-bit mode. As far as I can tell, it's exactly the same. I had heard
that some things might not work, but I can't find anything.
Should I stay in 64-bit mode? Is there any performance advantage?
Thanks,
Frank
David Empson
> What's the story with running Snow Leopard in 64-bit vs. 32-bit mode?
There isn't one that needs to concern the vast majority of Mac users.
This is actually a question about running the Snow Leopard KERNEL in
64-bit vs 32-bit mode.
The operating system supports 64-bit applications in either case, as
long as you have a 64-bit CPU such as a Core 2 Duo, Core i5/i7 or Xeon,
but not a Core Solo or Core Duo as they are 32-bit processors.
> I have an early 2009 iMac, with 4GB. Recently I tried booting it up in
> 64-bit mode. As far as I can tell, it's exactly the same. I had heard
> that some things might not work, but I can't find anything.
>
> Should I stay in 64-bit mode? Is there any performance advantage?
You might be able to find one if you looked hard, but I doubt most
people would notice. You might even find that there is a performance
disadvantage to running the kernel in 64-bit mode with only 4 GB of RAM,
because the 64-bit kernel will be tying up more memory and leave less
available for applications and caching.
Most of the performance advantages of 64-bit come from having a 64-bit
application instead of a 32-bit one, because most applications spend the
bulk of their execution time in the application space, not the kernel
space.
You don't need to run the Mac OS X kernel in 64-bit mode to use 64-bit
applications (unlike Windows).
The time applications do spend in the kernel tends to be brief and
limited by whatever I/O activity is being initiated, which generally
requires waiting for a peripheral to deliver the data. The end result is
that the 64-bit kernel makes a difference in the order of less than one
percent.
Applications which make heavy use of the kernel will benefit somewhat
more due to less overhead entering and exiting the kernel, and faster
execution while inside the kernel. Even in these cases, it is probably
only a few percent.
The real reasons that someone needs to run a 64-bit kernel are:
1. If the computer has more than 32 GB of RAM, it must use a 64-bit
kernel.
2. If the computer has plenty of RAM, the 64-bit kernel will confer a
small performance advantage, which will particularly benefit something
like a server that is doing a lot of network and disk I/O.
3. Developers of kernel extensions need to be able to run their computer
with a 64-bit kernel to test their kernel extensions.
Everyone else might as well not bother, except as a curiosity to see how
well it works.
The performance gain is negligible, and it might be a performance loss
depending on memory usage.
As you noted, the 64-bit kernel can cause compatibility issues, due to
kernel extensions which are 32-bit only (e.g. Apple's USB modem driver).
--
David Empson
dem...@actrix.gen.nz
Nigel
81f0fc34-e5f9-4ab6...@h2g2000vbd.googlegroups.com, "flarosa"
<fr...@franklarosa.com> wrote:
One thing I got caught with is printing from Apple apps that run in 64-bit
(preview, ilife etc). I couldn't print as the printer drivers don't work
with 64-bit apps so you need to force the app to run in 32-bit mode (go to
info and tick the 32-bit box - easy to do). And 32 vs 64 bit - most users
will see no real difference anyway
Nigel
Downunder
J.J. O'Shea
(in article <C732B74D.4FC16%no...@nowhere.com>):
Hmmm... _which_ printer drivers don't work in 64-bit mode? Right now I'm
running (for example) Safari in 64-bit mode and all of my printers work just
fine.
--
email to oshea dot j dot j at gmail dot com.
David Empson
> On Tue, 24 Nov 2009 19:28:29 -0500, Nigel wrote
> (in article <C732B74D.4FC16%no...@nowhere.com>):
>
> > On 25/11/09 4:47 AM, in article
> > 81f0fc34-e5f9-4ab6...@h2g2000vbd.googlegroups.com, "flarosa"
> > <fr...@franklarosa.com> wrote:
> >
> >> What's the story with running Snow Leopard in 64-bit vs. 32-bit mode?
> >>
> >> I have an early 2009 iMac, with 4GB. Recently I tried booting it up in
> >> 64-bit mode. As far as I can tell, it's exactly the same. I had heard
> >> that some things might not work, but I can't find anything.
> >>
> >> Should I stay in 64-bit mode? Is there any performance advantage?
> >
> >
> > One thing I got caught with is printing from Apple apps that run in 64-bit
> > (preview, ilife etc). I couldn't print as the printer drivers don't work
> > with 64-bit apps so you need to force the app to run in 32-bit mode (go to
> > info and tick the 32-bit box - easy to do). And 32 vs 64 bit - most users
> > will see no real difference anyway
>
> Hmmm... _which_ printer drivers don't work in 64-bit mode? Right now I'm
> running (for example) Safari in 64-bit mode and all of my printers work just
> fine.
All drivers supplied by Apple with 10.6 should be fine with 64-bit
applications.
If you have installed printer drivers for 10.5 or earlier on a 10.6
system (e.g. because the standard 10.6 driver doesn't work, or the
printer is not supported), they will be 32-bit only.
The problem is likely to be the Print Dialog Extensions (PDEs), which
implement printer-specific details in the Print dialog box. Since that
is running in the context of the appliction's process, they have to
match the architecture of the application. If you were using a very old
printer driver which had a PowerPC-only PDE, you'd probably have to run
the application via Rosetta.
I'm not familiar enough with the details of the print subsystem, but I'd
expect the printer driver itself would be running in a separate process,
so its architecture shouldn't matter.
--
David Empson
dem...@actrix.gen.nz
Nigel
1j9u564.1p76uvljmrxqhN%dem...@actrix.gen.nz, "David Empson"
<dem...@actrix.gen.nz> wrote:
David is right - all the apple supplied ones are fine. For me it was our
Toshiba e-studio networked printers at work. The driver is fine in 10.5 but
wouldn't work in 10,6 without a bit of permissions tweaking etc and will not
work on apps running in 64-bit
I am usually rather careful about upgrading - I had SL on my laptop for
weeks with very few issues before upgrading the work machines and I just
missed the printer issue (my bad). Eventually drivers will be updated but
it screwed me up for 2-3 days getting it sorted.
Nigel
Warren Oates
Nigel <no...@nowhere.com> wrote:
> I am usually rather careful about upgrading - I had SL on my laptop for
> weeks with very few issues before upgrading the work machines and I just
> missed the printer issue (my bad). Eventually drivers will be updated but
> it screwed me up for 2-3 days getting it sorted.
>
You know, I always thought of myself as a fairly intrepid "early
adopter" but I've actually dumped SL (not out of spite or anything: I
had a disk problem and I needed the drive that SL was installed on to
keep my backups running). I launched it a few times, and didn't see
anything I liked, and some stuff (QT X) that I really really thought was
really really silly. So I'm still with 10.5.8. Needs some software
updates too -- soon as LaCie send me a new power supply.
--
Suddenly he realized that he was alone
with a giant halfwit on a dark deserted street.
-- Chester Himes