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New 4GB DIMM's in iMAC Aluminum 20"?

M

mindframe

macrumors newbie
Original poster
Jun 29, 2008
7
0
SoHo Manhattan, NYC
Hi all,

I have an iMac 2.0GHz Intel Core 2 Duo (20-inch) MA876LL. I'm big into desktop virtualization (using VMware fusion) so obviously the upgrade to 4GB is key. I have 1GB now mostly because I have been using it as an internet terminal, but it's still real slow.

I would like to upgrade to 4GB- but I noticed they now sell 4GB DIMM's.

Will the BIOS/MB refuse 2x4GB DIMM's for a total of 8GB? Any hacks or upgrades I could do to get 8GB in this machine?


Also is the CPU socketed or soldered into the motherboard (I'm thinking the iMAC's use the same or similar motherboards as their laptops). If I could open this puppy up and drop in a 3GHZ C2Duo that would rock, but totally void warranty however.

Just some questions. If I want a faster 20" maybe the 2.66ghz I might just have to sell the one I have now and buy a refurb or one on ebay....


Thanks
Pat
 
mindframe said:
Hi all,

I have an iMac 2.0GHz Intel Core 2 Duo (20-inch) MA876LL. I'm big into desktop virtualization (using VMware fusion) so obviously the upgrade to 4GB is key. I have 1GB now mostly because I have been using it as an internet terminal, but it's still real slow.

I would like to upgrade to 4GB- but I noticed they now sell 4GB DIMM's.
Click to expand...

It will not see beyond 4GB ram even if it would boot with that memory.
 
what i might do is pickup one 4gb dimm, throw it in a slot and remove the 1gb. see if it boots.

then add the 1gb and see if it sees 5GB.

anyone know the command sequence to bring the boot phase into a "diag" mode kinda like the "ok" prompt on a sun workstation?
 
If it does indeed boot then we know the iMac is capable of addressing more ten the 4GB of memory stated in the system specifications.

My only concern with putting in 4GB and 1GB is that memory is supposed to be installed in matched pairs for optimal performance but it would be interesting to see if it works with more than 4GB of memory.
 
losierp said:
If it does indeed boot then we know the iMac is capable of addressing more ten the 4GB of memory stated in the system specifications.

My only concern with putting in 4GB and 1GB is that memory is supposed to be installed in matched pairs for optimal performance but it would be interesting to see if it works with more than 4GB of memory.
Click to expand...

Not really the Mac Mini will run with two 2GB sticks, but the computer will only be able to access 3GB of it.
 
yah matched pairs provide the best performance, but if the system sees 5GB then I'll purchase another 4GB DIMM right away and probably take the 1GB out and sell it.

If it doesn't work I'll just return it and act as a "clueless end user" lol


i'll keep the thread updated on my progress. I'm going to buy one on Tuesday or so, it might get here after the holiday...

If we can get 8GB in these puppies, that would make me VERY happy :)
 
gehrbox said:
Not really the Mac Mini will run with two 2GB sticks, but the computer will only be able to access 3GB of it.
Click to expand...

That's because of the chipset. It can't address more than... wait... I was going somewhere with this... I HAD a side to this... I just can't figure out how to word it properly.

Apple always understates the amount of RAM that you can put in their machines. The iMac DV can address 1GB, but Apple said the max was 512MB. Sometimes the limit they impose is due to the prohibitive cost of RAM at the time. Another example: the original Mac Pro was never touted to be able to use more than 16GB, but it, like the current one, can use 32GB. 4GB FB-DIMMs didn't exist at first, and when they started to come out, they were prohibitively expensive. Try ludicrously.
 
Hey there mindframe, please keep us posted about this. I think that lots of people would be curious to know about this. Thank you for the question.... we look forward to some definitive feedback!
 
I would be interested to see if this works as well, please do tell us if it does!
 
Tallest Skil said:
Apple always understates the amount of RAM that you can put in their machines. The iMac DV can address 1GB, but Apple said the max was 512MB. Sometimes the limit they impose is due to the prohibitive cost of RAM at the time. Another example: the original Mac Pro was never touted to be able to use more than 16GB, but it, like the current one, can use 32GB. 4GB FB-DIMMs didn't exist at first, and when they started to come out, they were prohibitively expensive. Try ludicrously.
Click to expand...

No, Apple does not ALWAYS understate the RAM. It has happened in the past, but is not an indicator that it is Apple's policy to do with all machines.

Apple's technical documents state unambiguously that the maximum readable device (chip) size is 1024 MBits, and the maximum readable number of devices on a module is 16. That means a maximum 2 GB module. Unless Apple is lying, that is the state of it until it can be shown to be wrong.

OP -- the Intel Core2Duo Macs use SODIMMs, not DIMMs.
 
PLEASE let us know if this works! :D

I'm on a Mac Pro with 8GB of memory and if the iMac could accept more than 4GB, even 5GB, I'd sell my Mac Pro and jump on the iMac in a heart beat. I know the previous iMacs could only support 3GB but if you put in 4GB it saw 3.3GB right?

Maybe it will see 4.3GB?
 
Here's where I found one initially:


http://www.pricewatch.com/system_memory/ddr2-667_pc2-5300_4gb.htm

Scroll down the page, it's a single stick 4GB 667mhz PC2-5300

The only problem that I might have, is that these 4GB sticks are for servers. They use a technology called buffered ECC, to prevent internal memory errors. I am not sure if iMac's- or any mac for that matter, can use bufffered ECC memory- simply because the pin outs are different, I THINK. Since they are meant for servers, and "registered" memory is for "personal computers".

Can anyone speak for hte pin outs of buffered ECC memory vs. registered memory? I don't wanna spend like $150 and find out it can't fit lol
 
mindframe said:
Here's where I found one initially:


http://www.pricewatch.com/system_memory/ddr2-667_pc2-5300_4gb.htm

Scroll down the page, it's a single stick 4GB 667mhz PC2-5300

The only problem that I might have, is that these 4GB sticks are for servers. They use a technology called buffered ECC, to prevent internal memory errors. I am not sure if iMac's- or any mac for that matter, can use bufffered ECC memory- simply because the pin outs are different, I THINK. Since they are meant for servers, and "registered" memory is for "personal computers".

Can anyone speak for hte pin outs of buffered ECC memory vs. registered memory? I don't wanna spend like $150 and find out it can't fit lol
Click to expand...


thats desktop ram..not laptop
 
Ahh crap. Well I guess that settles that! I should have bothered to read the instructions that came with the iMac on how to install memory, they probably would have showed a picture of the SODIMM ;) I figured since this machine is a "desktop" it would use desktop memory.

So I guess all the iMac is is a Macbook Pro / Powerbook / whatever they're calling them now in a low foot print case with a big ass display?

Thanks guys for saving me afew weeks of returns, RMA numbers, head aches, and restocking fees!

Pat
 
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