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RAM Question

Alesc said:
CL13 for the stock RAM :)
http://blog.macsales.com/33572-owc-unboxes-tears-down-the-late-2015-27-inch-imac-retina-5k
Click to expand...

Thanks!

I typed in the serial number from their picture of the ram and here are the complete specs for the 4GB modules that the iMac ships with:
http://www.deluxecomp.com/catalog/p...13-1-35v-low-voltage-mfr-p-n-hmt451s6bfr8a-rd.

Note that the manufacturer refers to the stock ram as being 1866MHz while Apple calls it 1867MHz, which can confuse people into thinking the OWC ram is the only "compatible" ram with the late-2015 iMac. From the searches I’ve done, OWC is the only seller using the term “1867MHz” to refer to their ram (https://eshop.macsales.com/search/1867). Their ram is also more expensive than other available options.

For 1866MHz ram, by searching Google for the term “1866 204 clxx” (where xx refers to the CL you want), I found CL10 from Crucial (Crucial Ballistix Sport), CL11 from OWC and Kingston (Kingston HyperX Impact Black), and CL13 from Crucial. Some of the online stores that sell some of these models are CDW, Adorama, Newegg and of course Amazon and OCW. Aside from OCW where ram is around $65-70 per 8GB, you can find ram at a rate of about $45-$55 per 8GB by going with Crucial or Kingston. At the moment, to my knowledge OCW is the only one who sells sticks of 16GB modules (and at a steep premium).

The best rates I could find for 8 GB modules:

For CL10, $88.99 for 16GB (2 x 8GB) of Crucial Ballistix Sport at Amazon (Prime).

For CL11, $109.99 for 16GB (2 x 8GB) of Kingston HyperX Impact Black at CDW ($111.99 on Amazon with Prime).

For CL13, $87.95 for 16GB (2 x 8GB) of Crucial at at Amazon (Prime).

Since the iMac ships with CL13, is it best to buy Crucial CL13 ram if I was only interested in adding ram to the 2 empty slots (2 x 8GB)?

I am beginning to think that it might be better to buy CL10 if there is a significant performance difference between CL10 and CL13. In that case, I would probably buy 4 x 8GB modules of Crucial Ballistix Sport ram to put one in each of the 4 slots (since I am still not sure if it is okay to mix both CL13 with CL10 together).

One last thing, if the iMac can take 2133MHz ram, is the performance boost big (at an equivalent CL) and how much hotter do you think it might get if at all?
 
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I'm also interested on what @KRMac asked. While I'm waiting for my top specced new 5K (sans RAM) to replace sweet old 2011 I'd like to know if anyone has an opportunity test if 5K works with DDR3L 2133Mhz RAM? I'm eyeing on the Kingston HyperX with CL11 which should be quite an update compared to the Hynix 1866 CL13 it has as factory option. I could always get faster (better than CL13) 1866 but before doing that I really wanna know if the motherboard will support 2133 or will it be rolled down to 1866 after powering the comp. Or will it not work at all...
 
majestice said:
I'm also interested on what @KRMac asked. While I'm waiting for my top specced new 5K (sans RAM) to replace sweet old 2011 I'd like to know if anyone has an opportunity test if 5K works with DDR3L 2133Mhz RAM? I'm eyeing on the Kingston HyperX with CL11 which should be quite an update compared to the Hynix 1866 CL13 it has as factory option. I could always get faster (better than CL13) 1866 but before doing that I really wanna know if the motherboard will support 2133 or will it be rolled down to 1866 after powering the comp. Or will it not work at all...
Click to expand...
It is not the motherboard who handle the RAM. The memory controller is in the Intel CPU. Even 2013 iMacs correctly handle 2133 MHz modules.
If you don't mix modules of different speed or different CL of course.
 
I went with the Kingston, mostly because I managed to get it a little bit cheaper than Crucial (in the UK). :D

I think at this level any slight differences (CL, even MHz) would be unnoticeable in anything other than a few points in benchmarks.
 
KRMac said:
Thanks!

I typed in the serial number from their picture of the ram and here are the complete specs for the 4GB modules that the iMac ships with:
http://www.deluxecomp.com/catalog/p...13-1-35v-low-voltage-mfr-p-n-hmt451s6bfr8a-rd.

Note that the manufacturer refers to the stock ram as being 1866MHz while Apple calls it 1867MHz, which can confuse people into thinking the OWC ram is the only "compatible" ram with the late-2015 iMac. From the searches I’ve done, OWC is the only seller using the term “1867MHz” to refer to their ram (https://eshop.macsales.com/search/1867). Their ram is also more expensive than other available options.

For 1866MHz ram, by searching Google for the term “1866 204 clxx” (where xx refers to the CL you want), I found CL10 from Crucial (Crucial Ballistix Sport), CL11 from OWC and Kingston (Kingston HyperX Impact Black), and CL13 from Crucial. Some of the online stores that sell some of these models are CDW, Adorama, Newegg and of course Amazon and OCW. Aside from OCW where ram is around $65-70 per 8GB, you can find ram at a rate of about $45-$55 per 8GB by going with Crucial or Kingston. At the moment, to my knowledge OCW is the only one who sells sticks of 16GB modules (and at a steep premium).

The best rates I could find for 8 GB modules:

For CL10, $88.99 for 16GB (2 x 8GB) of Crucial Ballistix Sport at Amazon (Prime).

For CL11, $109.99 for 16GB (2 x 8GB) of Kingston HyperX Impact Black at CDW ($111.99 on Amazon with Prime).

For CL13, $87.95 for 16GB (2 x 8GB) of Crucial at at Amazon (Prime).

Since the iMac ships with CL13, is it best to buy Crucial CL13 ram if I was only interested in adding ram to the 2 empty slots (2 x 8GB)?

I am beginning to think that it might be better to buy CL10 if there is a significant performance difference between CL10 and CL13. In that case, I would probably buy 4 x 8GB modules of Crucial Ballistix Sport ram to put one in each of the 4 slots (since I am still not sure if it is okay to mix both CL13 with CL10 together).

One last thing, if the iMac can take 2133MHz ram, is the performance boost big (at an equivalent CL) and how much hotter do you think it might get if at all?
Click to expand...

CL10 from CL13 is a 30% performance improvement,
 
gsingham said:
Could the 8gb single modules Apple are using be faster than the cheaper 4GB CL13?
Click to expand...
Apple is using 2x4 GB standard modules. They are not made from dragon scales because Apple sells it...
And they are using cheap modules: CL13 is not very fast today...
 
Alesc said:
Apple is using 2x4 GB standard modules. They are not made from dragon scales because Apple sells it...
And they are using cheap modules: CL13 is not very fast today...
Click to expand...
They are using 2 x 4 for the 8gb entry. If there are only 4 slots and offer a Maximum upgrade option of 32gb then by deduction they have to use 8Gb modules for 16 or 32gb
 
gsingham said:
They are using 2 x 4 for the 8gb entry. If there are only 4 slots and offer a Maximum upgrade option of 32gb then by deduction they have to use 8Gb modules for 16 or 32gb
Click to expand...
Never buy more than the 2x4GB to Apple: their (crappy) RAM is overpriced!! It is cheaper to buy afterwards third party faster RAM!! ;)
 
Alesc said:
Not in real life performance ;)
Click to expand...
Thanks for explaining the memory controller thing.. so I guess 2133 works at 2133 then. How much the real life performance difference between 2133CL11 would be to 1866CL11? I could basically get samsung 1866CL11 for half of the price of Kingston 2133CL11. I will do video editing, some after effects, davinci color correction and possibly some 3D in Maya or Cinema4D. They will be used on top specced 5K.
 
majestice said:
Thanks for explaining the memory controller thing.. so I guess 2133 works at 2133 then. How much the real life performance difference between 2133CL11 would be to 1866CL11? I could basically get samsung 1866CL11 for half of the price of Kingston 2133CL11. I will do video editing, some after effects, davinci color correction and possibly some 3D in Maya or Cinema4D. They will be used on top specced 5K.
Click to expand...
Half the price? Take the 1866MHz modules. The difference is hardly noticeable on real applications (on memory benchmarks, you can have 10 to 20% improvement, but it is only a memory benchmark). :)

You can read this: http://www.anandtech.com/show/6372/...-to-ddr32400-on-ivy-bridge-igp-with-gskill/11
 
I find it hard to believe that 2133 will function properly. Apple would have loved to say "our fastest memory every at 2x the speed" etc. They love bragging about stuff like that.

But they didn't. They used 1867. There must be a reason.

However, if test results come back, and 2133 does not overheat and survives a heavy workflow, I'll but it and try it
 
ohsnaphappy said:
I find it hard to believe that 2133 will function properly. Apple would have loved to say "our fastest memory every at 2x the speed" etc. They love bragging about stuff like that.

But they didn't. They used 1867. There must be a reason.

However, if test results come back, and 2133 does not overheat and survives a heavy workflow, I'll but it and try it
Click to expand...
I checked some benchmark scores from geekbench on 2014 5K iMac.. the leading score there was with 2133Mhz memory. So if it worked in last year's model, it must work this year's too
 
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ohsnaphappy said:
I find it hard to believe that 2133 will function properly. Apple would have loved to say "our fastest memory every at 2x the speed" etc. They love bragging about stuff like that.

But they didn't. They used 1867. There must be a reason.

However, if test results come back, and 2133 does not overheat and survives a heavy workflow, I'll but it and try it
Click to expand...
It works. There's a thread on this forum about people who have 2133MHz on last year Retina iMac.
And I have myself 1866MHz RAM on the late 2013 iMac (Apple sold it with 1600MHz RAM).
And all modules have the same 1,35V voltage, the heat is the same.

And Apple ships iMac with cheap RAM: money is the reason why they don't put 2133MHz modules in their machine. And the cost of 2133MHz RAM is IMO too high for the performance gain ;)
 
I'm pretty sure no matter what speed ram you put in, the MB runs it at the stock speed. In PC's you have to change the bios settings to speed up ram. I don't think macs self overclock. Now the quality of the ram may help in some way overall especially when stressing the memory, but I doubt the benchmark was running the memory at a faster speed than the stock mac is set to run at.
 
xgman said:
I'm pretty sure no matter what speed ram you put in, the MB runs it at the stock speed. In PC's you have to change the bios settings to speed up ram. I don't think macs self overclock. Now the quality of the ram may help in some way overall especially when stressing the memory, but I doubt the benchmark was running the memory at a faster speed than the stock mac is set to run at.
Click to expand...
The memory controller is in the CPU. If all the modules are the same, the CPU runs the RAM at the speed indicated in the SPD (a little chip in the RAM) or in the XMP profile if the modules have one.
And without configuration, the RAM runs at its proper speed.

My late 2013 iMac is said to support only 1600 MHz RAM by Apple. And I have that (I've also checked in CPUz: proper speed and timings):
201510_1866MHz.png


Actual i5 or i7 can handle 2400MHz memory at least (it is even more for "K" processors).
 
Layman's question here, but what difference does the MHz make when it comes to everyday tasks like photo editing (LR and Photoshop), video editing (Premiere) and general file management and running applications?
 
dcmontgomery said:
Layman's question here, but what difference does the MHz make when it comes to everyday tasks like photo editing (LR and Photoshop), video editing (Premiere) and general file management and running applications?
Click to expand...
Non noticeable IMO... A few percents of calculation time will be saved if you do a lot of encoding, compressing and other CPU demanding operations :)
 
So what is the best memory money can buy for this new imac then. Or should I say the "fastest" most reliable? Will heat spreader still fit 4 sticks?

By the way, I understand that the system reports the faster speed ram id, but is it actually running faster or at stock speeds. I did see a bench that showed a slight improvement in scores using 1600 ram.
http://apple.stackexchange.com/questions/73701/using-memory-with-a-higher-mhz-rating
 
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I ordered my 27" iMac with 16GB of memory from Apple (yeah I know, I should've just stuck with the stock 8GB). So while I can't change that now, I do want to upgrade to a total of 32GB. So here are my questions:

1) When ordering 16GB from Apple, do they use 4x4GB chips or 2x8GB chips? I don't know if I'll have 2 slots open or if I'll have to remove two of Apple's chips?

2) I assume it's okay to mix two of Apple's chips with two chips from a 3rd party vendor? It's look two 8GB chips from OWC is $134, so can someone point me to something comparable but perhaps less expensive?

http://blog.macsales.com/33330-owc-...2gb-for-latest-imac-with-27-retina-5k-display

Thanks!
 
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