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Upgrade question for iMac Intel Core Duo

G

gotroxs

macrumors newbie
Original poster
Nov 29, 2008
12
0
Arizona
I recently acquired an intel core duo 2.0 ghz iMac. I have been reading up that the processor can be upgraded to the intel duo 2 core. I am trying to find out what is the highest upgrade I can go. Anyone know of what the highest upgrade that can be done?

Thanks
 
OllyW said:
I thought you could go up to 3GB with a Core 2 Duo?
Click to expand...

Not sure about that. The memory controller is still the same as it's located in Northbridge which is a discrete chip. If you can put 3GB, then I would upgrade the CPU just because of that :p

I would assume the chipset is 945PM because it supports 667MHz DDR2 and that's what iMac uses plus it's the only chipset with PCIe x16. That supports 4GB of RAM according to Wikipedia

http://en.wikipedia.org/wiki/List_of_Intel_chipsets#9xx_Chipsets_and_3.2F4_Series_Chipsets

Just guessing though
 
Hellhammer said:
Not sure about that. The memory controller is still the same as it's located in Northbridge which is a discrete chip. If you can put 3GB, then I would upgrade the CPU just because of that :p

I would assume the chipset is 945PM because it supports 667MHz DDR2 and that's what iMac uses plus it's the only chipset with PCIe x16. That supports 4GB of RAM according to Wikipedia

http://en.wikipedia.org/wiki/List_of_Intel_chipsets#9xx_Chipsets_and_3.2F4_Series_Chipsets

Just guessing though
Click to expand...

only one way to find out!

OP - buy the CPU!
 
The memory will still be stuck at a 2GB limit. The real advantage of the Core 2 Duo is that it is about 25% faster at the same clock speed as the Core Duo. It also runs a little cooler and is 64bit internally so if Apple decides that 10.7 is going to be for 64bit CPUs only, you stand a better chance of being able to run it.
 
flopticalcube said:
The memory will still be stuck at a 2GB limit. The real advantage of the Core 2 Duo is that it is about 25% faster at the same clock speed as the Core Duo. It also runs a little cooler and is 64bit internally so if Apple decides that 10.7 is going to be for 64bit CPUs only, you stand a better chance of being able to run it.
Click to expand...

hellhammer doesnt seem to think so - as the chipset of the core duos supports it. what do you think?
 
Do some more Googling.....you're definitely stuck at 2GB.

EDIT: I take that back....with the Mac Mini Core Duo's you are definitely stuck at 2 GB....iMac may be different.
 
DoFoT9 said:
hellhammer doesnt seem to think so - as the chipset of the core duos supports it. what do you think?
Click to expand...

fhall1 said:
Do some more Googling.....you're definitely stuck at 2GB.

EDIT: I take that back....with the Mac Mini Core Duo's you are definitely stuck at 2 GB....iMac may be different.
Click to expand...

It's a memory controller problem. Even Windows machines of the same vintage are stuck at 2GB. Those that used the same chipset, that is.
 
flopticalcube said:
so if Apple decides that 10.7 is going to be for 64bit CPUs only, you stand a better chance of being able to run it.
Click to expand...

The EFI is still 32-bit, thus 10.7 would not run if it had only 64-bit kernel (this is very known "issue" with Mac Pro 1,1 and 2,1).

DoFoT9 said:
hellhammer doesnt seem to think so - as the chipset of the core duos supports it.
Click to expand...

I'm not 100% that it's the right chipset. As I said, it was just guessing and wondering. It could very well be a firmware limit as well, even though the chipset supported 4GB.

BTW, this article states that it uses the 945GM chipset that does support 4GB of RAM according to Intel.
 
Hellhammer said:
The EFI is still 32-bit, thus 10.7 would not run if it had only 64-bit kernel (this is very known "issue" with Mac Pro 1,1 and 2,1).
Click to expand...
Very true but it might not stop Apple from releasing some apps that are 64bit only, simply to drive people to upgrade.
I'm not 100% that it's the right chipset. As I said, it was just guessing and wondering. It could very well be a firmware limit as well, even though the chipset supported 4GB.

BTW, this article states that it uses the 945GM chipset that does support 4GB of RAM according to Intel.
Click to expand...

The root of the issue is that the mc does not recognize 2GB sodimms. Whether it was a hardware bug that was later corrected or a firmware limitation that Apple is not likely to address, I don't know.
 
flopticalcube said:
Very true but it might not stop Apple from releasing some apps that are 64bit only, simply to drive people to upgrade.
Click to expand...

As far as I know, 32-bit kernel can run 64-bit apps so that shouldn't be a problem. Not 100% sure does it change the story if EFI is 32-bit.

The root of the issue is that the mc does not recognize 2GB sodimms. Whether it was a hardware bug that was later corrected or a firmware limitation that Apple is not likely to address, I don't know.
Click to expand...

Might be that 4GB can be achieved when using four 1GB modules.

The first gen Core 2 Duo Macs use the same chipset as Core Duo iMacs (new chipsets didn't come until mid 2007 when Penryn was introduced) and they can take up to 4GB (only 3GB is recognized IIRC). Of course this is just in theory, there may still be a limit in firmware. I'm just bored so digging up old chipsets and seeing their specs :D

The only way to know is to try it :p
 
Hellhammer said:
As far as I know, 32-bit kernel can run 64-bit apps so that shouldn't be a problem. Not 100% sure does it change the story if EFI is 32-bit.



Might be that 4GB can be achieved when using four 1GB modules.

The first gen Core 2 Duo Macs use the same chipset as Core Duo iMacs (new chipsets didn't come until mid 2007 when Penryn was introduced) and they can take up to 4GB (only 3GB is recognized IIRC). Of course this is just in theory, there may still be a limit in firmware. I'm just bored so digging up old chipsets and seeing their specs :D

The only way to know is to try it :p
Click to expand...

Possible but using 4 1GB sodimms on an iMac would not work since they only have 2 slots on the white model and upgraded CD machines (at least minis) don't boot with 2GB sticks so it's either hardware or firmware. I k ow it was firmware on the early 09 minis that held back the 8GB max.
 
flopticalcube said:
Possible but using 4 1GB sodimms on an iMac would not work since they only have 2 slots on the white model and upgraded CD machines (at least minis) don't boot with 2GB sticks so it's either hardware or firmware. I k ow it was firmware on the early 09 minis that held back the 8GB max.
Click to expand...

I know iMac has only two slots, I was talking about the chipset in general (says 4GB on Intel's site, maybe that's with 4x1GB). Maybe it's a lousy FW limitation made by Apple then :(
 
i still think its not worth the afford , if you are good at selling ,sell the iMac on ebay and add the money the upgrade to core 2 duo (as i would never buy a used cpu )would have cost and you get a refurbished base 21.5 which has a 3.06 ghz core 2 duo and has 4 gb and a 1 TB harddrive inside and full warranty :cool:
 
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