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What RAM to buy to update new iMac launched today?

trsblader said:
I was on macsales looking at this for my upgrades, and they list their 32gb (8x4) from OWC as CL17 as well. Can't speak for the rest of it though.

macsales has a new section for the 2017 iMac's in case anyone else is looking at ram options and just wants to verify correct specs
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Weird-- OWC definitely had CL11 listed a few hours ago, but now it does say CL17 with a $299 price. Crucial it is then.
 
Robbo1 said:
Weird-- OWC definitely had CL11 listed a few hours ago, but now it does say CL17 with a $299 price. Crucial it is then.
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The OWC ram for 2015 says CL11 so they may have just copied that page and forgot to update the specs before publishing.
 
Azenha said:
The only difference between Crucial's 2017 iMac dedicated RAM and their regular RAM seems to be single vs dual ranked.
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And the Mac memory is Lead free and halogen free--- not sure how that matters either-- but the one labeled for Mac is only $10 more so why risk it?
 
Azenha said:
Apple has two webpages detailing the type of RAM needed for the 2017 27" iMac, but unfortunately they both have mistakes:

The support page mentions 204 pin SODIMMs (the correct is 260 pin): https://support.apple.com/en-us/HT201191

The online manual has the correct 260 pin but refers to the SODIMMs as PC4-2400 (the correct designation is PC-19200): https://help.apple.com/imac/mid-2017/#/apde7d36b188

So, in summary, the correct RAM type would be 260 pin DDR4-2400 SODIMM PC4-19200 memory.

There are 4 slots and you may use 4GB, 8GB and 16GB modules, for a maximum of 64 GB (4x16).

Regarding which brands and models specifically will work better with the 2017 27" iMac, nobody knows yet... Things like latency and other details could affect performance and stability. Past Macs have been known to be quite picky regarding 3rd party RAM, so I guess the safest bet is to wait for early adopters to get their hands on the computer and try out various RAM modules. That's what I'll do! ;)
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Does Dual rank and Single rank memory make much of a difference on a mac? I ask as you seem really knowledgeable about memory and from what I could find on the internet typically dual rank is faster on everything but latency on DDR4 but checking as I have some amazon rewards I'm using and they have ballistix memory but they don't yet carry the crucial mac memory for the mid 2017 iMac's.
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Robbo1 said:
And the Mac memory is Lead free and halogen free--- not sure how that matters either-- but the one labeled for Mac is only $10 more so why risk it?
Click to expand...

Sorry for the back to back posts but for me I have amazon credit and rewards and amazon doesn't have the crucial mac specific DDR4 Memory but amazon does have the Ballisix that for every other spec is the same. Also for the led free and halogen free I could be wrong but I think there's an asterisk next to those and further down on the page it says that's for DDR3 Memory.
 
jmantn said:
Does Dual rank and Single rank memory make much of a difference on a mac? I ask as you seem really knowledgeable about memory and from what I could find on the internet typically dual rank is faster on everything but latency on DDR4 but checking as I have some amazon rewards I'm using and they have ballistix memory but they don't yet carry the crucial mac memory for the mid 2017 iMac's.
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I honestly don't know... sorry.

Crucial does make single ranked RAM modules specifically for the 2017 iMac 27", whereas the generic non-Mac specific RAM modules are dual ranked. Not sure how relevant that detail is though, or if dual ranked RAM modules would have problems on the iMac.

http://eu.crucial.com/ProductDispla...-1&langId=-1&storeId=10152&modelCatId=2099009

http://www.crucial.com/ProductDispl...p_category=&parent_category_rn=&storeId=10151

I guess we'll have to wait for people to get their hands on the computers as they start shipping and see which RAM modules work best and which don't.
 
Last edited:
Hopefully we have some concrete results within the next few days regarding the Crucial 32GB CT2K16G4SFD824A RAM and if it works well with the 2017 iMac.

http://www.crucial.com/ProductDispl...p_category=&parent_category_rn=&storeId=10151

It does say incompatible with the 2017 iMac, but the specs are nearly identical to their Mac specific RAM. This may be a case where Crucial is just marking up the same/similar RAM modules marketed for Apple to get more $. Personally would go Crucial over OWC or other brands, have been using them in many different computers and their memory is always very reliable.
 
btrach144 said:
This is the RAM that I ordered. $216 for 32GB, free shipping, and no tax.

https://www.bhphotovideo.com/c/product/1208371-REG/crucial_ct2k16g4sfd824a_32gb_ddr4_2400_mhz.html
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Nice. Please keep us posted on your experience with that RAM on the new iMac when you get it.
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spinstorm said:
Would this RAM work?

https://www.amazon.co.uk/Corsair-CMK16GX4M2A2400C16-Vengeance-Performance-Desktop/dp/B017NW5NZY/ref=sr_1_3?ie=UTF8&qid=1496862403&sr=8-3&keywords=16gb+ddr4+2x8gb&th=1
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No, that RAM won't work as it those are 288-pin modules and the iMac needs 260-pin SODIMM modules.
 
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Azenha said:
I honestly don't know... sorry.

Crucial does make single ranked RAM modules specifically for the 2017 iMac 27", whereas the generic non-Mac specific RAM modules are dual ranked. Not sure how relevant that detail is though, or if dual ranked RAM modules would have problems on the iMac.

http://eu.crucial.com/ProductDispla...-1&langId=-1&storeId=10152&modelCatId=2099009

http://www.crucial.com/ProductDispl...p_category=&parent_category_rn=&storeId=10151

I guess we'll have to wait for people to get their hands on the computers as they start shipping and see which RAM modules work best and which don't.
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Thanks for the reply. Apple's website is pretty good for listing what is required
https://support.apple.com/en-ca/HT201191

And they make zero mention to the single vs dual memory ranking. To me this says it's not an issue otherwise it's a spec they'd hopefully list as a criteria.

Well I'd buy the suggested crucial if it was on amazon as that's where I have credit sitting...decisions. I will say for others that most of the information I've found suggest dual rank is faster than single rank in every metric but latency as dual rank requires 2 trips to the memory vs 1 with single rank. Copy/transfer speeds and etc are faster with dual rank but it's less noticeable with DDR4 than it was with DDR3.

Ballistix is advertised as gaming ram which usually anything advertised for gaming means they're great for photo and video editing which is what I'll be using it for but for anyone on the fence about the ranking I'd go with OWC or Crucial's Mac memory. The Ballistix has a marginally lower CL than those but it's also dual ranked memory.
 
This is right?

www.amazon.co.uk/gp/product/B01BIWMWVS/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

It looks to be the same as the crucial RAM on the site; but it doesn’t say for Mac which I assume is just because they like to name the same products more than once!?

EDIT: I assume this is the single ranked against dual ranked RAM mentioned a couple of posts ago. I ordered it from Amazon so I get delivery tomorrow.
 
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xgman said:
any "quality" sodimm 2400 ram should work and I've never had any problem in the past with 3rd party ram and several imacs.

Specs: DDR4 PC4-19200 • CL=16 • Unbuffered • NON-ECC • DDR4-2400 • 1.2V • 2048Meg x 64
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spinstorm said:
This is right?

www.amazon.co.uk/gp/product/B01BIWMWVS/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

It looks to be the same as the crucial RAM on the site; but it doesn’t say for Mac which I assume is just because they like to name the same products more than once!?

EDIT: I assume this is the single ranked against dual ranked RAM mentioned a couple of posts ago. I ordered it from Amazon so I get delivery tomorrow.
Click to expand...


I'm not sure what the difference is but the ram you linked to is 1024 x 64 whereas The crucial mac memory has 2048 x 64.

Here's the specifications to the memory you were asking about:
http://www.crucial.com/ProductDispl...p_category=&parent_category_rn=&storeId=10151
 
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Does anyone know the difference? The RAM came but I'm not sure I want to fit it until I know the answer?!
 
Anyone? Is it safe to use that RAM? As it's 1025x64 and not 2048x64
 
Can someone quantify the effect of the CL spec on actual expected performance? The Crucial RAM is rated with a CL of 17. In terms of percentage, how much faster would RAM with CL of 16 or 15 be?
 
I can confirm the 1024x64 RAM is fine.

My iMac booted and is happily working now on 24GB RAM with the two spare ports containing two 8GB sticks.
 
I'm going out on a limb and saying any DDR4 that will fit in that slot is going to load and work.
Kaby Lake works with damn near everything.
If it's 2400MHz then it is already overclocked RAM as DDR4 standard is 2133MHz, anything rated higher has been clocked higher, XMP.

So with that in mind, there have also been numerous test conducted to test overclocked RAM and where the sweet spot is and 2400 is pretty much it with 3000 being about where performance increases stop, anything above that there has been no noticeable performance increase yet with a significant price increase just to be able to say I have 3600MHz+ RAM.
 
RUQRU said:
Thanks for that. Engadet is talking about having to take the screen off to upgrade RAM. But that seems to be the 21" version. Why do they do that?
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An optimist would say the 21.5" 4K iMac has no user-accessible RAM tray because it is too packed with technology in a small space to have room for it, while the 27" does.

A cynic would say it is Apple phasing soldered RAM into the iMac line to increase their margins.

A realist would say that it is the former, but that with two years of work, it is now possible to make room for modular components, i.e. non-soldered RAM, but there is still no room for a user-accessible RAM tray.

:p
 
Brookzy said:
Could someone confirm that this Ballistix Sport RAM is okay? Seems fine to my eyes but the Crucial site says not compatible (I assume because it hasn't been updated yet).

http://uk.crucial.com/gbr/en/bls2c16g4s240fsd
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That's fine. As the person above said any DDR4 SODIMM will work. That looks exactly like the one standard RAM that is compatible just as you said but they say it isn't.

I put in different RAM (read up a few posts) and that's fine too.
 
Here's a question, I have a new 27" on the way, if I want to order an extra 16 or 32GB of ram, is it better to get everything up and running on it first and then install the ram, or should I just plop it in before I even turn it on?
 
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