iMac 2014 with 64 GB Ram?

[liamshy]

Hi Folks,

Just curious if anyone here has attempted to "hack" their 1st gen 5k iMac with 64 GB of Ram? (iMac15,1)

I am fully aware that *officially* this model only supports 32 GB ram. However I am wondering if anyone has attempted to install 64 GB to find out if this is a real limitation or a marketing limitation? I'd like to give it a go, but haven't found any documentation online of any previous attempts to make this work.

Cheers!

PS. Looking at getting 2 of these kits to try: https://www.amazon.com/Crucial-16GBx2-PC3L-12800-Unbuffered-204-Pin/dp/B011ISG132
204 pin DDR3L SO-DIMM. Dual voltage and can operate at 1.35V. So I believe this should fit and work! Barring any software blocks......

 

[nambuccaheadsau]

Well buy 4x16GB at $600 and let us know.

MacTracker advises still 32GB so the 16GB modules may not suit.

 

[liamshy]

Yes I will most likely make the purchase and just give it a shot. Just wanted to check first to see if anyone had tried already before I go through the motions. I will definitely update here with my experience. Again, I'm aware that the "official" support is only 32 gigs. Trying to see if we can break the rules though

 

[BornAgainMac]

Skylake chips set supports 64 GBs using only 4 slots. The 2014 version will not work with the 16 GB sticks or DDR4 16 GB(can't remember which). It shouldn't hurt to try it.

 

[liamshy]

Ahhh.... so it's a CPU limitation of Haswell?

Skylake chips set supports 64 GBs using only 4 slots. The 2014 version will not work with the 16 GB sticks or DDR4 16 GB

Can you support this with some kind of data/links?

 

[EugW]

Skylake chips set supports 64 GBs using only 4 slots. The 2014 version will not work with the 16 GB sticks or DDR4 16 GB(can't remember which). It shouldn't hurt to try it.

To be clear, if some people here didn't understand his comment:

The 2014 is NOT Skylake. The 2015 model is Skylake. While the 2015 iMac does not officially support 64 GB RAM, it actually does support 64 GB RAM, according to tests by OWC, and as reported by Everymac.com. However, the 2014 does not. EveryMac.com does not list any compatibility for 64 GB RAM for the 2014 models.

OP, don't waste your money.

 

[liamshy]

To be clear, if some people here didn't understand his comment:

The 2014 is NOT Skylake. The 2015 model is Skylake. While the 2015 iMac does not officially support 64 GB RAM, it actually does support 64 GB RAM, according to tests by OWC, and as reported by Everymac.com. However, the 2014 does not. EveryMac.com does not list any compatibility for 64 GB RAM for the 2014 models.

OP, don't waste your money.

Ya... I did some more digging and it seems pretty clear that it's a limitation of the Haswell / 4790K Devil's Canyon CPU. It does seem that this limitation is software based and there could potentially be a BIOS update that would allow for 64 GB, but as of right now that seems like a long shot. I still kinda want to try but it looks like 95% chance of failure.

Annoying since there is a history of being able to expand beyond the advised limits, but probably not in this particular case.

Cheers guys

 

[EugW]

Ya... I did some more digging and it seems pretty clear that it's a limitation of the Haswell / 4790K Devil's Canyon CPU. It does seem that this limitation is software based and there could potentially be a BIOS update that would allow for 64 GB, but as of right now that seems like a long shot. I still kinda want to try but it looks like 95% chance of failure.

Annoying since there is a history of being able to expand beyond the advised limits, but probably not in this particular case.

Cheers guys

Hmmm... That table may be misleading actually. For example, the 2017 27" officially supports 64 GB for most of the models. Only the base model doesn't list 64 GB compatibility (but it does support 64 GB).

 

[BornAgainMac]

Ahhh.... so it's a CPU limitation of Haswell?


Can you support this with some kind of data/links?

https://ark.intel.com/products/75122/Intel-Core-i7-4770-Processor-8M-Cache-up-to-3_90-GHz

No support for DDR4 memory. 32 GB upper limit. If it did support more, OWC would have advertised 64 GB for it.

 

[Glockworkorange]

https://ark.intel.com/products/75122/Intel-Core-i7-4770-Processor-8M-Cache-up-to-3_90-GHz

No support for DDR4 memory. 32 GB upper limit. If it did support more, OWC would have advertised 64 GB for it.

Yeah, OWC isn't going to miss out.

 

[nambuccaheadsau]

Really?

A BIOS update? I would doubt it sincerely.