Upgrading RAM in imac

Cris_L

Cris_L

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Can anyone shed some light..Ive got an i3 imac with 2x2GB RAM that I would like to expand. There are 2 slots free. I have read that there should be identical RAM in each slot..ie 2 x 2gb or 4 x 2 gb but not 2 x 2gb and 2 x 4gb combined. whereas some other places I've read say it is fine to do this.

So its weather I order 2 x 4GB giving me 12gb in total or order another 2 x 2gb giving me 8gb.

Does anyone know if it would be ok to mix size?
 
id always install the same in each slot, preferably from a specific kit (i.e. supplied in a pack of 2x whatever or 4x whatever sticks) that way you pretty much guarantee theyll all play nice together.

otherwise you could end up with sticks with different speeds, timings and latencies and theyll be trying to use settings that makes everyone happy etc.

id sell whats in there and buy new for the amount of memory you want to end up with.
 
Thanks Neil, does sound like a sensible option, perhaps sell whats there and install 2 x 4 so I can install another 2 x 4 at a later date.
 
Why not just get the 2 x 4gb and fit it in addition to your existing 2 x 2gb and see if you are happy with it? If not remove the 2 x 2gb. There shouldn't be an issue with 2 pairs of different capacity sodimms.
 
Just get on the Crucial site, they have a tool that will check your imac ans show you the correct ram available.

No problem at all mixing sizes, just don't mix speeds. They have to be in pair so 2x2 and 2x4 is fine

I have what your thinking of 12GB, no problems at all, and with the prices I would get the 2 X 4GB

Now if your is a late 2009 iMac and takes DDR3 PC3-8500 • CL=7 • Unbuffered • NON-ECC • DDR3-1066 •
I can sell you 2 X 2GB for a very reasonable £20 inc p&p

As I did your first choice then got 2 X 4GB later.
 
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hmm...according to mac upgrades and also crucial you can mix sizes but the speed must be the same ie 1333mhz. The crucial scanner recommends which RAM is suitable but I might still play it safe and plumb for the 2x4 for now.
 
whiteflyer said:
Just get on the Crucial site, they have a tool that will check your imac ans show you the correct ram available.

No problem at all mixing sizes, just don't mix speeds. They have to be in pair so 2x2 and 2x4 is fine

I have what your thinking of 12GB, no problems at all, and with the prices I would get the 2 X 4GB

Now if your is a late 2009 iMac and takes DDR3 PC3-8500 • CL=7 • Unbuffered • NON-ECC • DDR3-1066 •
I can sell you 2 X 2GB for a very reasonable £20 inc p&p

As I did your first choice then got 2 X 4GB later.
Click to expand...

Thanks for the offer mark, mine is a late 2010 model so I think I might opt for 2x4 from crucial and either leave in or remove what i currently have.
 
I have 2x2 and 2x4 in mine, with the 2x4 from crucial. No problems with running like that at all.
 
I do have one question, which I'm sure someone will know.

You have to fit pairs in each bank, but are the ram bank left and right or top and bottom.

What I mean is should you have 2 X 2GB in the top two slots and 2 x 4GB in the bottom slots, or should it be 2 x 2GB in the right-hand slots and 2 x 4GB in the left-hand slots

I only ask as when I checked mine for this thread I saw the following in the about this mac. Which looks like I have a 2gb and a 4gb in each bank.

Screenshot2011-07-06at102549.jpg
 
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whiteflyer said:
No problem at all mixing sizes, just don't mix speeds.
Click to expand...

the only problem is that while they can be the same rated speed they can have different timings/CAS/latency ratings which will differ between brands/model memory.

What I mean is should you have 2 X 2GB in the top two slots and 2 x 4GB in the bottom slots, or should it be 2 x 2GB in the right-hand slots and 2 x 4GB in the left-hand slots
Click to expand...

depends on the board in the mac. for example some motherboards the dual channel runs on slots 1 and 2 then 3 and 4, others run on slots 1 and 3 then 2 and 4. i would consult apple for that info.
 
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whiteflyer said:
I do have one question, which I'm sure someone will know.

You have to fit pairs in each bank, but are the ram bank left and right or top and bottom.

What I mean is should you have 2 X 2GB in the top two slots and 2 x 4GB in the bottom slots, or should it be 2 x 2GB in the right-hand slots and 2 x 4GB in the left-hand slots

I only ask as when I checked mine for this thread I saw the following in the about this mac. Which looks like I have a 2gb and a 4gb in each bank.
Click to expand...

Top and bottom.
 
So currently mine has empty in the top two slots and the 2gbs in the bottom 2 slots (as whiteflyer above).

I assume then if I were to mix size I should put the 4gbs into the two empty slots rather than swap things around.
 
Cris_L said:
So currently mine has empty in the top two slots and the 2gbs in the bottom 2 slots (as whiteflyer above).

I assume then if I were to mix size I should put the 4gbs into the two empty slots rather than swap things around.
Click to expand...


Just been on the Apple discussions site, and a few on the same topic. If you buy an iMac from Apple with the 12GB memory it will be placed as mine is

2 x 2 in the top slots and 2 x 4 in the bottom slots. Also they are of the opinion that it won't make any difference to performance no matter how you have them, just so long they are all the same speed.
 
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