Retina iMac 1866 MHz RAM Working

[Chippy99]

Hi!

I just ordered a 5K iMac with the i7 processor and 8GB of RAM. Can I use the two 16GB modules (see attachment) that I originally bought for my "old" 2012 iMac?

I'm not sure if the timings will be compatible.

Cheers,
Chris

On it's own (i.e. remove the Apple memory first) then maybe. Adding to the Apple memory (24GB total), I would not risk it.

The issue you have is not just the timings, its the voltage. The later Intel chipsets really want 1.35v memory, whereas the old ones needed 1.5v. The 2012 iMac needed 1.35v, but it was "OK" to install 1.5v memory, as indeed I have done for the past 18 months. But the newer iMacs are more sensitive and I am not sure you would get away with it.

 

[ix400]

On it's own (i.e. remove the Apple memory first) then maybe. Adding to the Apple memory (24GB total), I would not risk it.

The issue you have is not just the timings, its the voltage. The later Intel chipsets really want 1.35v memory, whereas the old ones needed 1.5v. The 2012 iMac needed 1.35v, but it was "OK" to install 1.5v memory, as indeed I have done for the past 18 months. But the newer iMacs are more sensitive and I am not sure you would get away with it.

The modules I have are 1.35V as far as I know. Maybe I just should try it.

 

[Chippy99]

The modules I have are 1.35V as far as I know. Maybe I just should try it.

Sorry - didn't realise that. In that case, go for it. They will almost definitely work alone in your new iMac and they may well work just fine with the existing ram. They are the same CAS timing as your existing ram, so you have decent chance of it working fine.

 

[xgman]

I think I'm going to try these 1866 sticks. Someone said they worked fine in the 2013 27" imac.

http://www.amazon.com/Crucial-Ballistix-PC3-12800-204-Pin-BLS8G3N18AES4/dp/B00DSGLM9G

Is it recommended to run the Apple Diagnostics with 3rd party ram?

 

[xgman]

There's no perceptible difference between RAM speeds all things else being equal. Benchmarks will show very small differences with certain applications (and no differences with most), and with extremely RAM intensive applications, there can be benefits over the long term.

Yes seems the case as shows here:

https://forums.macrumors.com/threads/retina-imac-1866-mhz-ram-working.1815203/

 

[majestice]

I would go safe with these Kingston HyperX Impact SODIMM which are for Apple computers, and they run at CL9 which a a lot better the the stock CL11 RAM that comes with the iMacs

Part Number: HX316LS9IBK2/16
Specs: , DDR3L, 1600MHz, CL9, 1.35V,

http://www.kingston.com/en/memory/search?DeviceType=2&Mfr=APP&Line=iMac&Model=90781

I'm planning to get 4x8gb Kingston HyperX 2133MHz CL11 RAM. I believe the stock option from apple is Hynix and that is not even CL11.. it is CL13

EDIT: ok this seems to be an old thread. Not about the newest iMac 5K