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ZaniCuzi

macrumors newbie
Original poster
Dec 28, 2014
3
0
Hello,

I am thinking of upgrading the RAM in my 2011 27 inch iMac to 12GB. I plan to keep using the stock 2x2GB RAM already installed in the computer. I'm also planning to order a 1x8GB stick from Crucial. My question is will 2x2GB+1x8GB sticks work? Can I use only three slots of the available four?

I cannot find these answers anywhere, and it would be great to hear some advice!
 

stiligFox

macrumors 65816
Apr 24, 2009
1,483
1,328
10.0.1.3
Hello,

I am thinking of upgrading the RAM in my 2011 27 inch iMac to 12GB. I plan to keep using the stock 2x2GB RAM already installed in the computer. I'm also planning to order a 1x8GB stick from Crucial. My question is will 2x2GB+1x8GB sticks work? Can I use only three slots of the available four?

I cannot find these answers anywhere, and it would be great to hear some advice!

It should work fine but it won't be as efficient as using all the same specced RAM. I upgraded a 2010 or 2011 iMac that my friend had in a similar matter; he had 1x8GB + 1x4GB RAM and it booted up and recognized the RAM just fine.
 

ZaniCuzi

macrumors newbie
Original poster
Dec 28, 2014
3
0
It should work fine but it won't be as efficient as using all the same specced RAM. I upgraded a 2010 or 2011 iMac that my friend had in a similar matter; he had 1x8GB + 1x4GB RAM and it booted up and recognized the RAM just fine.
Sounds good. Thanks!
 

tyche

macrumors 6502
Jul 30, 2010
413
65
2009-2011 iMacs support non-parity memory and can use 3 slots (in theory). Not something I would do personally. As listed below, you will probably have to juggle the memory around, 1 dimm in the top, 2 in the bottom pair.

Use Small Outline Dual Inline Memory Modules (SO-DIMM) that meet all of these criteria:

iMac (Mid 2011)
PC3-10600
Unbuffered
Nonparity
204-pin
1333MHz DDR3 SDRAM

Additional notes:
i5 and i7 Quad Core iMac computers come with both top memory slots populated. These computers will not start up if only a single DIMM is installed in any bottom slot; these computers should operate normally with a single DIMM installed in any top slot.
 

ZaniCuzi

macrumors newbie
Original poster
Dec 28, 2014
3
0
2009-2011 iMacs support non-parity memory and can use 3 slots (in theory). Not something I would do personally. As listed below, you will probably have to juggle the memory around, 1 dimm in the top, 2 in the bottom pair.

Use Small Outline Dual Inline Memory Modules (SO-DIMM) that meet all of these criteria:

iMac (Mid 2011)
PC3-10600
Unbuffered
Nonparity
204-pin
1333MHz DDR3 SDRAM

Additional notes:
i5 and i7 Quad Core iMac computers come with both top memory slots populated. These computers will not start up if only a single DIMM is installed in any bottom slot; these computers should operate normally with a single DIMM installed in any top slot.
Yes, I'm thinking that I will have to play "musical RAM sticks" in order to place them into the correct slots. The worst that could happen is to do something like what stiligFox did and install a 1x2GB + a 1x8GB, and the total would be only 10GB of RAM, which would still be better than the 4GB of RAM that I already have. I will upgrade the RAM to 16GB or even 32GB in the future. This is why I really want to use the 8GB RAM sticks instead of 2x4GB ones.
 
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