Question re iMac memory upgrade

[Slobodan Blagojevic]

I have the latest iMac 27", which came with 8 Gb memory (2x4). There are four spots for memory, giving the theoretical maximum of 32 Gb (4x8). I know that the general advice is to upgrade memory in pairs, so my question is: can I just add another pair of 2x8, for the total result of 24 Gb? In other words, it would be 2x4 (existing) + 2x8 = 24. Or it has to be 4x8, in which case I would have to waste the original memory? Or, to preserve the current memory, should I just add another 2x4 combo, for the total of 16?

[degrub]

As a pair of 4's or 8's (total 16 or 24).
Just have to match Apple's specs. OWC are good. There are others - Crucial, etc.

Frank

[KirbyKrieger]

Go to Crucial's or OWC's site, put in your machine specs, and buy what they specify.

I suspect that you won't see much performance improvement (if any) with any more RAM than 16 GB.  I don't have test links at hand, but they are pretty easy to turn up.  Since you already have eight, and OEM memory is relatively cheap, put in 16 more.  If you happen to have 1 x 8 or 2 x 4 lying around, use it and spend your money elsewhere.

After 16 GB RAM, I'd put money in, first, an SSD, and second an upgraded GPU.  The SSD will bring much more performance boost than increasing RAM.

Fwiw, I think the "must be pairs" is from old PC's.  I'm pretty sure (= don't rely on this) that current CPU's will address memory in any configuration (and I think Mac's have been able to for a long time).  OWC does recommend installing memory in matched pairs "for best performance".

[Jeremy Roussak]

I have the latest iMac 27", which came with 8 Gb memory (2x4). There are four spots for memory, giving the theoretical maximum of 32 Gb (4x8). I know that the general advice is to upgrade memory in pairs, so my question is: can I just add another pair of 2x8, for the total result of 24 Gb? In other words, it would be 2x4 (existing) + 2x8 = 24. Or it has to be 4x8, in which case I would have to waste the original memory? Or, to preserve the current memory, should I just add another 2x4 combo, for the total of 16?

Slobodan,

I added a pair of 8Gb cards to mine, giving 24. I thought about dumping the two existing 4Gb cards and using 4x8, but it really didn't seem to be worth the cost. I find it works well.

Jeremy