leopard, 4gb RAM recognized on Pre-Santa Rosa Mac???

xUKHCx

Administrator emeritus
Jan 15, 2006
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The Kop
Interesting, wasn't this discussed ad nauseam with the consensus outcome being that it was a hardware limitation.
 

Consultant

macrumors G5
Original poster
Jun 27, 2007
13,293
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Interesting, wasn't this discussed ad nauseam with the consensus outcome being that it was a hardware limitation.
Yeah, but in the hardware, there is software running running somewhere. You can physically put 4gb of RAM in it, but if it can see only 3gb, then somewhere alone the line, something limits the ability to use / see 4gb.

It may most likely be a fluke in some software or misreporting, but I have a white intel iMac, and i would love to use 4gb of ram. In fact, I am ordering a pair of 2gb ram right now and see what happens.

Edit: add: besides, it's MacRUMORS. =p Just want to see whether it's true or not.
 

4God

macrumors 68020
Apr 5, 2005
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Mmmm...I was just looking for that post, I thought I saw something to that effect but with all the excitement I couldn't find it. I too would like to know if that's true. I have a 24" white iMac that has 3 gigs now and would like to move to 4 gigs if it works.
 

xUKHCx

Administrator emeritus
Jan 15, 2006
12,587
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The Kop
In the discussion it was report that it was a hardware limit as even though the processor may be 64 Bit the logic board is only 36 Bit. Hence the limitation. I have the same iMac and would love for 4 GBs also so please report back, what is the delivery time.
 

whiteyanderson

macrumors 6502
Aug 12, 2007
378
0
Hollywood, California
yep please let us know. 24" white iMac here and would love the extra GB of memory. getting the wife a 20" aluminum one this xmas and would be nice to order a couple 2GB sticks so i can have 4GB and she can have 3.
 

4God

macrumors 68020
Apr 5, 2005
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....I have a non santa rosa Macbook Pro that before Leopard would only recognize 3 of the gigs of ram I installed. Now with Leopard the system monitor sees all 4gb instead of 3gb. I guess it wasn't a hardware limitation after all.....
My only concern is that maybe the extra ram is recognized, however still not accessible or effectivley usable because of the hardware limitation of the logic board chipset.
 

Consultant

macrumors G5
Original poster
Jun 27, 2007
13,293
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Deciding whether to get the 4gb via either
18004Memory.com $150 or
OWC $171

(I am not going to get Samsung original for $300... as I paid only $850 for the iMac)
 

maverick808

macrumors 65816
Jun 30, 2004
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Scotland
The limit is a hardware one, and I'm sorry but there is no way around it. The system might know that there's 2x2GB chips in there but there's no way it can address the whole 4GB. I'd advise anyone that thinks they have 4GB working on their non SR machines to not just look in the About this Mac box but also to check Activity Monitor, where they will see that the little pie chart showing the memory the system is using is less than 4GB. Sorry.
 

4God

macrumors 68020
Apr 5, 2005
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.....I'd advise anyone that thinks they have 4GB working on their non SR machines to not just look in the About this Mac box but also to check Activity Monitor, where they will see that the little pie chart showing the memory the system is using is less than 4GB. Sorry.
I'd like to see a screenshot of that little pie chart from anyone who tries.
 

Anonymous Freak

macrumors 603
Dec 12, 2002
5,198
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Cascadia
Now this has me curious... I have an original 15" MacBook Pro (2.0 GHz Core Duo, not Core 2 Duo.) The underlying chip architecture is theoretically capable of more than 4 GB of RAM (Intel has used "Physical Address Extension" to allow 32-bit-only chips to access more than 4 GB of RAM for over a decade now,) and since the chipset allows at least 3 GB of RAM on a Core 2 Duo, I wonder if Leopard will let me put 3+ GB of RAM into my original MacBook Pro?
 

maverick808

macrumors 65816
Jun 30, 2004
1,130
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Scotland
Now this has me curious... I have an original 15" MacBook Pro (2.0 GHz Core Duo, not Core 2 Duo.) The underlying chip architecture is theoretically capable of more than 4 GB of RAM (Intel has used "Physical Address Extension" to allow 32-bit-only chips to access more than 4 GB of RAM for over a decade now,) and since the chipset allows at least 3 GB of RAM on a Core 2 Duo, I wonder if Leopard will let me put 3+ GB of RAM into my original MacBook Pro?
No, the original MBP CD has a hardware limit of 2GB. No matter what you do you'll never be able to put any more than that in it.
 

Consultant

macrumors G5
Original poster
Jun 27, 2007
13,293
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Now this has me curious... I have an original 15" MacBook Pro (2.0 GHz Core Duo, not Core 2 Duo.) The underlying chip architecture is theoretically capable of more than 4 GB of RAM (Intel has used "Physical Address Extension" to allow 32-bit-only chips to access more than 4 GB of RAM for over a decade now,) and since the chipset allows at least 3 GB of RAM on a Core 2 Duo, I wonder if Leopard will let me put 3+ GB of RAM into my original MacBook Pro?
With the Core Duo, it's been said neither the processor nor logic board recognize >3gb of ram.

With Core 2 Duo pre-santa rosa, the processor can handle 4gb of ram, BUT the logic board is said to unable to handle >3gb of ram. However we are curious to see what happens with Leopard for this config with 4gb of ram.

With Santa Rosa Core 2 Duo, it supports 4gb.
 

Malakas07

macrumors member
Jun 13, 2007
63
0
Awww man. I saw this thread and got all excited when I saw a good couple of replies.

So much for my 4gb dreams.
 

CanadaRAM

macrumors G5
With the Core Duo, it's been said neither the processor nor logic board recognize >3gb of ram.
No, CoreDuos cannot recognize more than 2 Gb or RAM.

With Core 2 Duo pre-santa rosa, the processor can handle 4gb of ram, BUT the logic board is said to unable to handle >3gb of ram. However we are curious to see what happens with Leopard for this config with 4gb of ram.
As already posted, it will accept 4 Gb, and report 4 Gb in the System Profiler, but only 3.3 GB is available to be used. The hardware memory controller on the motherboard steals the top 700Mb of addresses for hardware addressing of other components. So Leopard does not change this at all. The addresses are simply not available for the OS to read and write to the memory.
 

proc

macrumors member
Oct 29, 2007
66
0
The Netherlands, Europe
Tried and verified

I have tried Leopard with my iMac 24" (Late 2006) which has 2 modules of 2GB making a total of 4GB. Using Leopard it shows 4GB in systemprofile and 4GB in Activity which I found odd, as the same machine shows 4GB in systemprofile but 3GB in Activity using Tiger...

I did find Leopard a tad slow (it seemed it was already finished indexing), whereas using Tiger it is quite fast.

It is equipped with the default 250GB HDD (haven't changed that yet), the memory modules are two OCZ branded modules type OCZ2MV6672G.
 

4God

macrumors 68020
Apr 5, 2005
2,117
241
My Mac
Tried and verified what? Were you doing something ram intensive that you saw it actually using more than 3.3 gigs of ram? Screenshot of pie chart please.
 

proc

macrumors member
Oct 29, 2007
66
0
The Netherlands, Europe
Checked Activity monitor

I have watched systemprofiler showing 4GB and Activity Monitor showing 4GB of memory also in my late 2006 iMac 24" in Leopard. In Tiger systemprofiler showed 4GB but Activitymonitor showed only 3GB (as I expected). I don't know what's going on: can Leopard actually use 4GB now? I have seen 32MB of free memory at a certain point of use (was doing email import using Mail and some other stuff). I thought this wasn't possible with thelate 2006 iMac 24" (November 2006). Can somebody enlighten me?
 

psonice

macrumors 6502a
Jul 22, 2005
968
0
In the discussion it was report that it was a hardware limit as even though the processor may be 64 Bit the logic board is only 36 Bit. Hence the limitation. I have the same iMac and would love for 4 GBs also so please report back, what is the delivery time.
If the logic board is 36bit, then it supports 64gb of ram! More likely it supports 32bit, which is 4gb.

What I find odd though is this "3gb" limit. The chipset would support either 2 or 4gb I'd have thought, 3gb would be "31.5 bit" which wouldn't work. What I have seen though is on an alu imac, osx sees the full 4gb limit but windows sees only 3.3gb. That's because I'm running 32bit windows, and it reserves part of the memory range for various I/O stuff - and it's a definite software limit as the mac sees more. So it could be that tiger was doing the same thing as windows xp, and allocating 700mb to I/O, while leopard is doing something else. I doubt it, but it's conceivable. Post some screenshots :)
 

andresrw

macrumors member
Jun 5, 2007
40
0
No, CoreDuos cannot recognize more than 2 Gb or RAM.


As already posted, it will accept 4 Gb, and report 4 Gb in the System Profiler, but only 3.3 GB is available to be used. The hardware memory controller on the motherboard steals the top 700Mb of addresses for hardware addressing of other components. So Leopard does not change this at all. The addresses are simply not available for the OS to read and write to the memory.
But with 4 gb the system will bre much faster indeed?
I am waiting to received 2 2gb from OWC $176 paid i expect is good.
Canada can you tell me at how much can I sell my original 2 gb ram installed in my 15" 2.2 Macbook Pro?
Thanks.
 
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