64 Bit Operation and the Mac Pro 2.66 x2 Dual-Core Computer

[AllanKane]

Hi Motu People,
I am about to update to DP8 and was wondering if my computer will deliver the full 64 Bit power. Today, I went into a computer shop in Toronto ( Yes....the home of Mayor Rob Ford!) and was going to buy an additional 8 gigs of ram. The sales guy told me that my model, will play 64 bit software but I will not be able to use more then 4 GB ram due to some EFI problem. I was disappointed as Apple tech told me it would work in full 64 bit mode. ( I am running SNOW LEOPARD as Maverick will not work).

Has anybody used this computer with DP 8 or other and experienced full 64 bit operation.
Am I wasting my time upgrading ram?

Thanks,

Allan

[MIDI Life Crisis]

Machines earlier than 3,1 (2008) won't run in 64 bit.

From here:

http://www.everymac.com/systems/apple/m ... specs.html

Pre-Installed MacOS: X 10.4.7 (8K1079) Maximum MacOS: X 10.7.5*
Details: *This system can run the last version of OS X 10.7 "Lion" if upgraded to at least 2 GB of RAM. However, although it has a 64-bit processor, it has a 32-bit EFI and cannot boot in 64-bit mode. It also does not support "OpenCL" running the default video card or the other build-to-order video cards that were offered via custom configuration. Please also note that OS X Lion is not capable of running Mac OS X apps originally written for the PowerPC processor as it does not support the "Rosetta" environment.

[HCMarkus]

I'd research the issue a tad... although the machine may not be able to boot the OS into 64 bit mode (hence the end of the line at Snow Leo), it may well run 64 bit apps. I have never dealt with 1,1 vintage mac pros, and what MLC says may be true, but just to be sure, do a little Googling before you write off your machine as incompatible with 64 bit DP.

[MIDI Life Crisis]

Isn't it true that if you can't boot into 64 bit mode, you can't access more than 4GB of RAM in DP? Sure, you can work around that to some degree with bridges, IAC, and such, but the question is "...if my computer will deliver the full 64 Bit power... and it appears that unfortunately, the answer is no. Maybe some of that power, but not the whole enchilada.

[James Steele]

Isn't it true that if you can't boot into 64 bit mode, you can't access more than 4GB of RAM in DP?

No... that is NOT true!

We've been round and round on this one and I'm surprised it persists. You do NOT need to boot in the the 64-bit kernel in order to run an app in 64-bit mode and access more than 4GB!! I was doing it on my MacPro1,1.

Please I hope we can put this to rest.

[James Steele]

Hi Motu People,
I am about to update to DP8 and was wondering if my computer will deliver the full 64 Bit power. Today, I went into a computer shop in Toronto ( Yes....the home of Mayor Rob Ford!) and was going to buy an additional 8 gigs of ram. The sales guy told me that my model, will play 64 bit software but I will not be able to use more then 4 GB ram due to some EFI problem. I was disappointed as Apple tech told me it would work in full 64 bit mode. ( I am running SNOW LEOPARD as Maverick will not work).

HE IS WRONG!!!!

We seem to go over this one over and over. I had a MacPro 1,1. True... you cannot boot that machine into the 64-bit kernel. So maybe the OS might not be able to access more than 4GB of RAM... however...

YOU DO NOT NEED TO BE BOOTED INTO THE 64-BIT KERNEL TO RUN DP (OR OTHER APPS) IN 64-BIT MODE THUS ACCESSING MORE THAN 4GB OF RAM!!!

And yes... on the MacPro 1,1, actually, 10.7.5 Lion is as far as you can go on that machine, but you won't want to (at least I didn't as I felt my machine was more sluggish.) I would continue to run Snow Leopard on it. And really the only thing that might hold you back from buying RAM is if you can't get it cheap enough since you won't be able to use it in later Macs should you trade up to a newer machine in the future. That said, if you come across a deal on some extra RAM cheap, then go for it because DP8 can indeed access more than 4GB on a MacPro 1,1 on Snow Leopard when it is launched in 64-bit mode.

[MIDI Life Crisis]

I'm just reporting what Apple specs are. I know we've been around the block, but... full 64 bit features appear to NOT be possible on a pre 3,1 machine, regardless of bold and/or capped text. I'm not making this stuff up. I'm providing reasonably reliable sources and links in response to the inquiry. That's all. If there's a contrary reliable source that's not anecdotal, I have yet to find it. Nothing personal.

[HCMarkus]

I did a little checking, 'cause I was thinking, it turns out correctly, that (with all respect) MLC is a tad misinformed... as Mr. Steele has, in the interim, advised us.

Random Mac Guy
"All you are unable to do is boot the 64-bit kernel, not something you'll miss."

OWC:
"Snow Leopard can run 64-bit applications. Even though the kernel itself is running in 32-bit mode, most of that which we use every day are 64-bit apps. Apps like Safari, Mail, iCal, and – most importantly – the Finder itself, all run in 64-bit mode. About the only Apple apps not running in 64-bit are the iLife apps, which will likely see an update soon. 64-bit versions of third-party applications though, such as Photoshop, will also be released over time from their respective vendors."

MacWorld
"Applications running in Snow Leopard will have access to a full 16 exabyte virtual address space, just the same as if they were running in a 64-bit kernel. As a result, there’s very little difference between booting into the 64-bit kernel and the 32-bit kernel in current Mac systems... So, bottom line: If you’ve got a Core 2 Duo or Xeon based Mac — any Intel Mac not running a Core Duo or Core Solo processor — you’ll be able to run applications in 64-bit mode, which will in turn be able to take advantage of faster 64-bit registers and math routines as well as access massive amounts of memory.

Bottom Line: You will be able to use DP8 under Snow Leo and address as much RAM as the machine will hold - that's 32 Gigs - but your CPU will probably top out before then.

Before you start buying loads of RAM for your 1,1 (new, its more than twice as expensive as DDR3 used in 2009 or later), consider upgrading to a used Mac.

[James Steele]

I'm just reporting what Apple specs are. I know we've been around the block, but... full 64 bit features appear to NOT be possible on a pre 3,1 machine, regardless of bold and/or capped text. I'm not making this stuff up. I'm providing reasonably reliable sources and links in response to the inquiry. That's all. If there's a contrary reliable source that's not anecdotal, I have yet to find it. Nothing personal.

It's not only in other threads here, it's elsewhere on the net. I've posted links before too this and it's not just anecdotal, I've observed it firsthand when I had my MacPro 1,1. There's a distinction between booting into the 64-bit kernel and running a 64-bit app.

Here's one link:

http://macperformanceguide.com/SnowLeop ... penIn64Bit

[MIDI Life Crisis]

If the source I cited is incorrect so be it. I defer to those who know better. To the o/p: go for it.

[James Steele]

Before you start buying loads of RAM for your 1,1 (new, its more than twice as expensive as DDR3 used in 2009 or later), consider upgrading to a used Mac.

THIS! Unless you have a line on some used RAM from a friend selling a machine (perhaps he gives you the extra RAM before putting on craigslist or something) or some other really good deal, you might thing twice on stocking up on those old modules.

[James Steele]

If the source I cited is incorrect so be it. I defer to those who know better. To the o/p: go for it.

I'm sorry MLC. I didn't mean to jump you. Just don't want the O/P to miss out if he's got a good deal on some RAM. Again though, like has been pointed out, you'd want to think twice before spending too much on those old 667 fully buffered modules that are really odd ducks these days.

[AllanKane]

RAM upgrade worth the investment? I don't think so.
Many thanks to all for your comments.


Allan

[AllanKane]

Is my Intel Mac 64-bit compatible?
Yes, if your Mac has a Core 2 Duo (note the "2") or Xeon processor. No, if your Mac has a Core Duo or Core Solo processor. Check the Hardware Overview in System Profiler to find out.

My Mac, has a Xeon Processor so I think it appears to be 64 Bit operational.

[AllanKane]

Another Question:
I have a 2.3 GHZ Macbook Pro i5 with 16 GB Ram. Is this computer going to be faster then
the 2 x 2.66 GHZ Dual-Core Mac Pro?

Thanks again to all who have contributed to this blog.