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Justin1020304

macrumors newbie
Original poster
Jan 19, 2016
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i have a Mid 2011 27inch IMac i5 processor with 4GB of ram. It takes nothing for it to become slow due to the ram getting over used.. So I'm planning on switching to 16 GB or 20 gb if I keep in the ram that's in it now. I heard placing the ram certain ways can make it better somehow. Right now 2 spots are filled 2 2GB sticks in the top going horizontal. And I'm getting 2 8GB ram sticks. Do I just stick them in the 2 bottom horizontal slots at the bottom? Also heard the iMac can go to 32 gb correct? Any advice would help.. Don't want to mess up..
 
You are correct - you can put up to 32GB in your iMac. Check out Crucial for some ideas on what they offer and to get some ideas.

http://www.crucial.com/usa/en/compa...re-i5-(27-inch---ddr3)-mid-2011#memoryResults

Also ifixit.com will show some pictures on how to do it. And yes, you push them in and make sure they are seated firmly. If there are any issues you will know when you start it up. If there are do not panic. You can reseat them or change the order they are in. It won't hurt it but if there is an issue it will let you know!
 
Just make sure you insert them next to each other. So:

Slot 1 - 2 GB
Slot 2 - 2 GB
Slot 3 - 8 GB
Slot 4 - 8 GB

Always add two the same modules. The SDRAM controller operates in dual-channel mode. So each read/write operation expects access to 2 modules simultaneously.
 
loekf,
Just make sure you insert them next to each other. So:

Slot 1 - 2 GB
Slot 2 - 2 GB
Slot 3 - 8 GB
Slot 4 - 8 GB

Always add two the same modules. The SDRAM controller operates in dual-channel mode. So each read/write operation expects access to 2 modules simultaneously.
So Slot 1 is in the top left (according to About this Mac) and then to the right of that is Slot 2? or is it the one below Slot 1? thats what I'm confused about..
 
loekf,

So Slot 1 is in the top left (according to About this Mac) and then to the right of that is Slot 2? or is it the one below Slot 1? thats what I'm confused about..

If it came with chips in those two top slots, then they are "bank one", slots 1 and 2. The second row would be "bank two" slots 3 and 4 reading left to right.

The machine will not operate with one module in bank one. That's why they ship with two fours instead of one eight.

Dale
 
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If it came with chips in those two top slots, then they are "bank one", slots 1 and 2. The second row would be "bank two" slots 3 and 4 reading left to right.

The machine will not operate with one module in bank one. That's why they ship with two fours instead of one eight.

Dale
Thanks i understand now, so i should just be able to put in the 2 8 GB sticks with no problem then since there are just 2 spots left?
 
Thanks i understand now, so i should just be able to put in the 2 8 GB sticks with no problem then since there are just 2 spots left?

Should be. The size isn't important as long as they are installed in matched pairs like 2 4gig or 2 8 gig chips. Buy them in pairs from the same supplier, too. Not one from Crucial and one from another supplier.

If you have something wrong, it just won't start. Won't blow it up.

Just do a Google on Upgrading 2011 iMac RAM.

Dale
 
If it came with chips in those two top slots, then they are "bank one", slots 1 and 2. The second row would be "bank two" slots 3 and 4 reading left to right.

The machine will not operate with one module in bank one. That's why they ship with two fours instead of one eight.

Dale
Strange, IIRC I ran my 2011 27" iMac with only one module to isolate a problem once.
I thought the reason they shipped with 2x modules was because they got dual channel support that way?
 
Strange, IIRC I ran my 2011 27" iMac with only one module to isolate a problem once.
I thought the reason they shipped with 2x modules was because they got dual channel support that way?

Could be that it only works in dual channel mode with two. Just going off what I read on the Apple iMac support site.

Dale
 
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