Is 24" iMac truely 64-bit?

[kixsand]

I've asked this question knee deep in another thread but thought it might be worth while to start a new one spcifically to address this question.

The Intel Core 2 Duo processor is a 64-bit processor but does the rest of the architecture surrounding that processor allow for 64-bit processing -- the front side bus etc?

I've seen comments that essentially characterize the new iMacs as having a 64 bit processor chained to a 32 bit motherboard. Despite hunting high and low I've not been able to find any good explanations as to what the real story is.

I'm between the 24" iMac and a Mac Pro and essentially want to know if the iMac will be able to make use of 64-bit processing in exactly the same way that the Mac Pro can or is there some limitations built into the computer?

Please enlighten and unburden me!

Thanks,

Darren

 

[PlaceofDis]

i'm not sure to be exact, but is there a specific reason why you need 64-bit? are you going to be running apps that are written only for 64bit?

 

[Eidorian]

iMac Core 2 Duo
- 64-bit processor
- Able to run 64-bit applications
- Unable to address more then 32-bit of RAM (Well 4 GB minus some change.)

 

[mkrishnan]

I was googling around, and I haven't seen any definitive posts of experiences using XP-64 or Vista-64 on any Mac other than a Mac Pro. It's probably all a drivers thing, though... the hardware on the MP is probably easier for XP to recognize....

 

[kixsand]

i'm not sure to be exact, but is there a specific reason why you need 64-bit? are you going to be running apps that are written only for 64bit?

I'm just thinking of the future...possibly near future...when operating systems and software alike is all 64 bit.

darren

 

[PlaceofDis]

I'm just thinking of the future...possibly near future...when operating systems and software alike is all 64 bit.

darren

certainly won't be near future. too much is written in 32bit and would have to be done from scratch with no real benefit. OS X will be both 64/32 for a long time to come, and thats because virtually no apps are 64 bit because they don't need to be and work better as 32bit.

 

[Eidorian]

The iMac Core 2 Duo is 64-bit. Just don't expect to be able to ADDRESS your 64-bits of RAM.

If you want to FULLY benefit from a 64-bit architecture (other then running 64-bit programs) get a Mac Pro or wait for the 965 chipset to go mobile.

64-bit applications are useful when you want to commit large data sets to memory. Otherwise if you're using less then 4 GB, you're better off with 32-bit applications.

 

[kixsand]

The iMac Core 2 Duo is 64-bit. Just don't expect to be able to ADDRESS your 64-bits of RAM.

Eidorian,

You're posts have been very helpful...maybe if you could just dumb down your statement about addressing ram for me. Talk to me like I'm an idiot.

You won't offend me.

Cheers,

Darren

 

[Eidorian]

A 32-bit program can only address up to 4 gigabytes (2-3.8 GB real) of system RAM.

A 64-bit program can address up to 16 exabytes of system RAM (17,179,869,184 gigabytes).

The iMac can currently on take up to 3 GB of RAM. So you can run a 64-bit application on the iMac. You just USE more then the 3 GB of system RAM that's there.

The Power Mac G5 and Mac Pro can have much more then 4 GB of RAM installed. So those machines can fully take advantage of a 64-bit application's memory addressing abilities.

 

[Sun Baked]

The Mac Pro can handle 32GB of RAM today, if you can afford to buy it.

It can also handle a buttload of virtual memory inside the machine with the built-in drive bays and external RAID options.

If you need a bunch of physical and virtual memory for your applications, the iMac and Mac Pro will offer drastically differing experiences.

Even if you wait for the next generation iMac with its 8GB RAM limit, it will still pale in comparison to what the Mac Pro offers today.

 

[The General]

It has a 64-bit processor and runs AMD64/EM64T Linux perfectly fine.

So, yes. It is a 64-bit system.

The chipset is what limits the RAM capacity.

 

[gnasher729]

The Intel Core 2 Duo processor is a 64-bit processor but does the rest of the architecture surrounding that processor allow for 64-bit processing -- the front side bus etc?

I've seen comments that essentially characterize the new iMacs as having a 64 bit processor chained to a 32 bit motherboard. Despite hunting high and low I've not been able to find any good explanations as to what the real story is.

Mac OS X 10.4 Tiger is mostly a 32 bit operating system. Very little software runs in 64 bit mode (Mathematica is an exception). Mac OS X 10.5 Leopard will be a 64 bit operating system. This is important for applications that need significantly more than 2 GB of RAM for themselves, it is some advantage for applications that are absolutely performance critical. To most users, it doesn't make the slightest difference.

The Core 2 Duo processor is a full 64 bit processor. Anyone who claims otherwise hasn't got a clue.

The motherboards in the MacBooks and iMacs allow using up to 3 GB of RAM. If that is enough, go for it. If that isn't enough, get a MacPro. Look at the price of 2 GB chips, then tell me if you want more than 3 GB. If you can afford 4 GB, and you want that much memory, get a MacPro. If the price of two 2 GB chips gives you a heart attack, get the iMac. The "64 bit"-ness of the motherboard is just how much RAM it can use (and you may not have noticed, but 64 GB of RAM needs only 36 bit, not 64). The other important thing for speed is how wide the connection between processor and RAM is, and that is completely independent of 32 or 64 bit.

Again: Is 3 GB enough or not? That is the question you have to answer.

 

[Eidorian]

Tiger - 64-bit in console
Leopard - seamless 64-bit in console and GUI.

 

[dllavaneras]

Isn't the chipset stuff supposed to be fixed with the upcoming Santa Rosa platform?

 

[Eidorian]

Isn't the chipset stuff supposed to be fixed with the upcoming Santa Rosa platform?

Yes, the mobile 965 chipset resolves the 32-bit addressing limitation.

Just find me a laptop that'll take more then 4 GB of RAM though.

 

[kixsand]

I've got it now!

Thanks so much for the patiently delivered and detailed posts ... very helpful.

So it all comes down to ram. My gameplan at the offset was to equip the iMac with 2 gb of ram. If I were to get the Mac Pro I would have left it with the stock 1gb. In both cases I would add more as prices came down and as usage required it.

I've wondered why the odd 3 gb maximum on the iMac...if I understand you correctly anything more than 3 gb wouldn't be accessible anyway...and so that makes sense to me now.

I may end up with the Mac Pro anyways...it is such a safe purchase...no matter what the future holds the system is guaranteed to be relevant for years to come -- just add money!

The iMac is blazingly fast today and the form factor is something that I really do like and appreciate...I have a 17" iMac right now and still think that it is a really great looking computer. I just haven't enjoyed not being able to make upgrades along the way and have truly been suffering with pedestrian performance over the past couple of years. I don't want to find myself in a similar situation a couple of years from now.

I've sort of decided not to do anything until Leopard is released. I'm sure that I will agonize over this right to the end.


Cheers,

darren

 

[VanNess]

Again: Is 3 GB enough or not? That is the question you have to answer.

640K ought to be enough for anybody.

 

[gnasher729]

I've wondered why the odd 3 gb maximum on the iMac...if I understand you correctly anything more than 3 gb wouldn't be accessible anyway...and so that makes sense to me now.

Actually, a little bit more than 3 GB could be accessible: There is 4 GB address space, and some (256 MB or 512 MB) goes to your video card, and a bit more is lost to other hardware.

Dell sells laptops with very similar motherboards, but lets you plug in two 2GB chips. You only get 3 1/4 or 3 1/2 GB usable RAM (the rest is just lost). Apple could probably do that as well, but if you look at the price of a 2 GB chip, and the price of a 1 GB chip, you get very little extra usable memory for an awful lot of money.

 

[eenu]

I've asked this question knee deep in another thread but thought it might be worth while to start a new one spcifically to address this question.

The Intel Core 2 Duo processor is a 64-bit processor but does the rest of the architecture surrounding that processor allow for 64-bit processing -- the front side bus etc?

I've seen comments that essentially characterize the new iMacs as having a 64 bit processor chained to a 32 bit motherboard. Despite hunting high and low I've not been able to find any good explanations as to what the real story is.

I'm between the 24" iMac and a Mac Pro and essentially want to know if the iMac will be able to make use of 64-bit processing in exactly the same way that the Mac Pro can or is there some limitations built into the computer?

Please enlighten and unburden me!

Thanks,

Darren

I answered you about this in the other thread!

 

[kixsand]

I answered you about this in the other thread!

Ya....you said...

"What would be the point of putting a 64bit chip in a 32 bit architecture!?"

Not particularly illuminating or helpful. Others on this thread were able to suffer this fool a little more gladly and formulate a cohesive explanation to support their points of view.

You might even know of that which you speak but you didn't give me much reason to believe that you did.

Cheers,

 

[eenu]

I think my explanation is pretty sound to give you a definative answer. No i didn't go into simple mans terms as to why but that isn't what your initial question in that thread asked.

 

[kixsand]

I think my explanation is pretty sound to give you a definative answer. No i didn't go into simple mans terms as to why but that isn't what your initial question in that thread asked.

You're not making yourself look any better. Walk away.

 

[eenu]

You're not making yourself look any better. Walk away.

Neither are you, google would have provided you with all the info you needed.

[REMOVED AS DEEMED HARSH]

Using google, '64 bit' would return a top link of:

http://en.wikipedia.org/wiki/64-bit

Which would have told you everything you needed to know. Hence why it got up my nose. Society and forums today seem to breed people with a lack of research skills. I'm not digging personally on you as you are by far and away not alone but thats why you got an answer from me like you did!

EDIT: Whilst forums are for help and we are happy to help you we are not here to bring information to you which is so so so simply found. Using the term '64 bit' on a search of this forum or google would have provided you the info. Not only did you post in one thread with the question but you opened a new one asking the same things!

 

[kixsand]

There now...you see...we got to the heart of the issue.

You think that there are too many people posting questions that could be easily answered with a little research and it drives you a little bit batty -- "gets up your nose" as you would say.

So when you read my post you took offence and decided to post a snarky comment designed to point out my ineptitude...which is entirely your perogative to do...I don't mind. Just don't pretend you were trying to be helpful when we all know that you weren't.

I actually did google "64-bit iMac" and read the article that you site. And, while it did confirm that the Intel Core 2 Duo is indeed a 64-bit processor it didn't answer my original question as to whether or not there was something about the configuration of the iMac that prevented it from being "truely 64-bit" -- was it hamstrung by other system limitations not related to the processor itself. I read a whole bunch of posts on this site and others that I thought might deliver clarity but never got what I was looking for. So I started a new thread on the topic.

Some fantastic posts on this thread went into great detail to explain exactly the limitations of the iMac system bus in addressing memory and how that would theoretically limit performance of the iMac in some situations...none of which were particularly relevant to my usage needs.

So...sorry if I was a bit harsh in response to your invective but I didn't think it was warranted in this situation.

Darren

 

[eenu]

all the information you required was in the wiki link though granted it wasn't in simple terms.

Peace