Max. amount of RAM for iMac core2 duo

azscp

macrumors member
Original poster
Nov 9, 2006
41
0
What is the maximum amount of ram I can install in my 20" iMac core2 duo? Can she handle 4GB? Crucial states the max. amount per slot is 2GB. Just confirming before I purchase.

Is crucial preferred over OWC, Samsung, Kingston or Micron?

So many choices. I get a little confused.
 

kaltsasa

macrumors 6502a
Jan 9, 2002
584
13
Kellogg IA
There's some sort of arbitrary hardware or software limitation capping the Core 2 iMacs at 3 Gigs. Theoretically they should handle 4, in reality its 2+1. I've got 3 gigs in my iMac and it's nice. Parallels runs like butter. I buy OWC RAM, they've always had good prices, good products, and good support. A great company.
 

CanadaRAM

macrumors G5
It's a hardware limitation of the memory controller on the Core2Duo logic boards. You can physically install 4 Gb ( 2 x 2 Gb) but the memory controller can only make 3.3 Gb available to the OS, because certain hardware resource addresses hog the addresses between 3.3 and 4.0 Gb (note- they don't actually use the RAM, they just preempt the addressing in that area from use by memory)

This is solved in the MBP Santa Rosa chipset, which can map those hardware addresses out of the memory space, and therefore can utilize the full 4 Gb RAM.
 

4God

macrumors 68020
Apr 5, 2005
2,109
229
My Mac
....You can physically install 4 Gb ( 2 x 2 Gb) but the memory controller can only make 3.3 Gb available to the OS, because certain hardware resource addresses hog the addresses between 3.3 and 4.0 Gb (note- they don't actually use the RAM, they just preempt the addressing in that area from use by memory).
Has anybody tried this yet on a C2D iMac?
 

jimbama

macrumors newbie
Oct 5, 2006
27
0
I think the max is 3GB (1x 1GB + 1x 2GB).
The OWC website has the following:

All iMac Intel Core 2 Duo models have two user-accessible memory slots for up to 3GB of total memory supported. Installing memory in pairs allows for maximum memory performance, although additional performance is also attained with the maximum 3GB Memory Configuration.

Any real world difference between the two? I have always assumed that I would be best served by maxing out the RAM (1x 1GB + 1x 2GB) vs. matching pairs with less total RAM (1x 1GB + 1x 1GB).