The real 64bit difference is...?

net26

macrumors member
Original poster
Aug 30, 2006
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I'm looking to buy a mbp, and i can get an awesome deal for the 2ghz core duo version (like 1600€) from my mac dealer (400€ less), it has an english keyboard (the default here is german :S ), 1.5GB ram(!!!) and I can pick it up today.

so my question is, what will i be missing out on when leopard gets released given that it will not have a core2duo processor with 64bit technology?

i don't really NEED to buy it now, but it seems like an excellent deal, it looks like the retailer is trying to get rid of it because they can't sell it with the ENG keyboard. though i don't much care for the merom speedbump, the 64bit thing has got me asking all sorts of questions, namely will i be missing out on some leopard features or it is just a matter of speed, which, as i said, isn't all that important (i'm still running a athlonXP2000+ PC for my cad stuff and i've never noticed it not being sufficient).

cheers
 

Patch^

macrumors regular
Mar 11, 2005
240
0
Great Britain
I am not really an expert on this sort of thing, so don't blame me if I'm wrong lol.

But from my recollection, to take advantage of 64Bit Technology you need to have more that 4GB of memory I think (something like 5GB,6GB or 8GB etc). Where as the MBP and most laptops in General only support 2GB of memory, So at the moment I can't see them having more memory unless they update the design.

You also have to have 64Bit applications to see any difference, by having a 64Bit processor you won't really make your 32Bit apps run any faster than on a 32Bit processor. Plus a lot of applications aren't even 64Bit yet.

I could be wrong, but I'm sure I heard something like it on this forum :confused:

Hope this helps in someway :) .

Edit: Here is a Wikipedia link for more help - http://en.wikipedia.org/wiki/64_bit
 

cube

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May 10, 2004
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You won't be able to run applications that have been compiled as 64-bit-only.
 

net26

macrumors member
Original poster
Aug 30, 2006
72
0
cube said:
You won't be able to run applications that have been compiled as 64-bit-only.
hmm... that just brings up more questions :D like will SW developers stop coding 32bit apps in the foreseeable future?

thanks for your replies!

cheers
 

Chaszmyr

macrumors 601
Aug 9, 2002
4,263
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net26 said:
hmm... that just brings up more questions :D like will SW developers stop coding 32bit apps in the foreseeable future?
Absolutely not, at least not for any sort of app that any consumer might use.
 

Nutter

macrumors 6502
Mar 31, 2005
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London, England
No, they won't, as Chaszmyr says. Aside from the fact that there are going to be a lot of 32-bit processors around for a long time, there's no need to compile in 64-bit unless the application needs to use more than 4 GB RAM. That's very, very few applications.
 

cube

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You can compile in 64-bit for some increased performance, even if the application is supposed not to need more than 4GiB of virtual memory.
 

TBi

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Jul 26, 2005
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For the G5 the only benefit of 64 bit was more addressable memory. However on Intel (and AMD) it is a totally different matter as 64-bit mode doubles the amount of registers available to the processor. This speeds up 64-bit programs on 64-bit processors. There will be a noticable gain (however this has been negated on intel before because the cpu doesn't work as well as the Athlon64's but i haven't seen the Core2Duo in 64-bit yet).
 

miles01110

macrumors Core
Jul 24, 2006
19,269
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The Ivory Tower (I'm not coming down)
Yes the only difference is the amount of memory the chip can address. 32-bit chips can handle 2^32 bits of information, which is around 4 GB of memory. 64-bit chips can address 2^64 bits, which is.....a lot.

I might add that part of the reason the Macbooks and Macbook Pros can "only" handle 2 GB of memory is due in part to space considerations...there isn't a whole lot of room to fit in larger sticks.
 

cube

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May 10, 2004
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The registers are wider, instructions operate on wider operands, there can be more registers.

A 64-bit chip does not necessarily support a 64-bit address space. It can be 48-bit virtual and 40-bit physical, for example.
 

RacerX

macrumors 65832
Aug 2, 2004
1,504
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Patch^ said:
But from my recollection, to take advantage of 64Bit Technology you need to have more that 4GB of memory I think
That is a little backwards... to take advantage of more than 4GB of memory you need to have 64 bit technology.

The primary (early) advantage of 64 bit processing is actually in the word size.

The best way to think of this is the words we use everyday. Imagine if you were restricted to words that were only 4 letters (or less) in length. How many more words would you need to be able to say the same thing that you could if you were restricted to words of 16 letters (or less)*.

By having longer word length you can increase your vocabulary and same more with fewer words... or, in other words, say more faster.

This is why so many computer companies started heading down the 64 bit road long before they were able to reach the 32 bit memory limit.

My Silicon Graphics Indy is a 64 bit workstation from 1994. The maximum amount of memory it can handle is 256 MB. This is a physical limitation of the hardware rather than the processor or software (seeing as the version of Irix I use is also 64 bit).

Of course the major advantages of 64 bit processing have been eclipsed by the ever increasing processor speed (the same way the RISC technology doesn't have the same impact that it once did). So today, in this era of processors that are so much faster than the average person could really need, the advantage that comes from 64 bit is not the word size, it is the memory size. Being able to give apps more than 4 GB of memory to run in is the advantage that will be most noticeable (be it in Photoshop, 3D apps or video editing apps).



* Exercise: To illustrate this point about word size, attempt to replace all words within this post that are longer than 4 letters in length with words (or combinations of words) that are no longer than 4 letters.
 

Sun Baked

macrumors G5
May 19, 2002
14,874
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With the switch to the 64-bit Merom you might be able use the entire 4GB limit of the current chipset. I hope.

When the new chipset comes, you will get another bump to 8GB.

---

Not sure about the bump to a full 4GB, but it should be likely with this chipset.

So that alone might be a good reason to wait for Merom, you might not need 4GB now but in 2-3 years it might seem like a good idea.

Or wait until 2007 for the 8GB chipsets to arrive.

If you need more, the Mac Pro should handle 32GB with 4GB FB-DIMMs.
 

hagjohn

macrumors 6502a
Aug 27, 2006
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Pennsylvania
Having a x64 bit AMD Windows system, I can tell you that anyone doing any intensive processing (games, video processing, etc...) will want a full 64 bit system (OS, programs and processor) as it will be so much quicker.

I hope to soon have a 64 bit macbook as soon as its released.
 

mkrishnan

Moderator emeritus
Jan 9, 2004
29,777
12
Grand Rapids, MI, USA
hagjohn said:
Having a x64 bit AMD Windows system, I can tell you that anyone doing any intensive processing (games, video processing, etc...) will want a full 64 bit system (OS, programs and processor) as it will be so much quicker.
Are there actually games that are written for XP64, using 64-bit APIs to advantage?
 

Sun Baked

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May 19, 2002
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TBi said:
My sarcasm-o-meter went to overload when i read the original twice as fast quote :)
Mine only overloads if you read the original quote twice as fast. ;)
 

TBi

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Jul 26, 2005
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Sun Baked said:
Mine only overloads if you read the original quote twice as fast. ;)
It didn't overload, it just went (close) to overload on the scale! I took care to read it slowly so as not to damage the sensitive sarcasmo-detector.
 

TBi

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wonga1127 said:
64-bit can handle and un-godly amount of RAM, and really won't make much difference for the end consumer.
Um and they get access to twice as much registers (in X86-64) and thus increases the speed of applications as they don't have to access their cache as much.

(G5 chips operate differently and don't get any speed boost from 64 bit (AFAIK))
 

D3LM3L

macrumors regular
Mar 31, 2005
122
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Detroit
mkrishnan said:
Are there actually games that are written for XP64, using 64-bit APIs to advantage?
Flight Simulator 2004 performs much, much better on an 64-bit system (only with Windows XP x64 installed).