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Sam Marks

macrumors member
Jul 5, 2019
90
25
I installed 32GB (2x16GB) of Timetec Hynix RAM 2667Ghz in my iMac 2019 i9 9900K (from Amazon) and it works very well.

Now, I have in total 40GB of RAM and the system is very stable, silent and with an excellent performance.
 
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codernova

macrumors member
May 13, 2019
93
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sick z33

macrumors 6502
Sep 20, 2008
295
4
Does anyone know the difference between these 2 Crucial 32gb kits? Trying to decide for my 2019!

CT2K16G4SFD8266

CT2K16G4S266M
 

marzfreerider

macrumors 6502
Jun 13, 2014
363
254
Canada
Does anyone know the difference between these 2 Crucial 32gb kits? Trying to decide for my 2019!

CT2K16G4SFD8266

CT2K16G4S266M


I'm using the first one you listed for just over 3 months with no issues. The only difference I can think is one was released last year and the second one just recently this year. The FD8266 wouldn't show as compatible for the 2019 on Crucial's own website, but there have been quite a few people who have used this with no issues. The specs match on both, so they just made some to make sure it can say its 100% compatible.
 

codernova

macrumors member
May 13, 2019
93
32
I installed 32GB (2x16GB) of Timetec Hynix RAM 2667Ghz in my iMac 2019 i9 9900K (from Amazon) and it works very well.

Now, I have in total 40GB of RAM and the system is very stable, silent and with an excellent performance.

JUST installed these as well, booted up first try (leaving the existing ram alone) to 40GB. :)
 

fujitasenpai

macrumors newbie
Dec 24, 2018
15
31
Does anyone know the difference between these 2 Crucial 32gb kits? Trying to decide for my 2019!

CT2K16G4SFD8266

CT2K16G4S266M


Seems like the only difference is the environmental standards (lead-free, halogen-free).
 
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alisalem

macrumors regular
Apr 12, 2013
158
123
Mississauga, ON
CT2K16G4SFD8266 here
 

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Shivetya

macrumors 68000
Jan 16, 2008
1,669
306

whosthis

macrumors member
Aug 21, 2008
99
44
Used the same. Now I just need to find ways to consume it all

1) Create a RAM disk
2) Install Windows virtual machine on it
3) Perform the gazillion updates
4) Delete the machine / Unmount the disk
5) Be happy, you didn't hurt your SSD. :cool:
 
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whosthis

macrumors member
Aug 21, 2008
99
44
Hi guys, waiting for my i9 iMac to arrive soon, was thinking to go for a 64GB of total RAM, but I found these Samsung sticks which are very similar that OWC used, but costs a almost 2 times less, have anyone tried them?
https://www.scan.co.uk/products/32g...MItLzuyLnz4QIVy7ftCh1WFw6DEAQYASABEgJW1fD_BwE
Those are exactly the modules I installed in my machine (4 of them) - they work just perfectly.

Also, I never had a problem with Samsung memory modules. But you do find quite a number of faulty OWC modules here in the forums. I honestly think most of the OWC stuff is highly overrated (they offer a great range of products, but - let's face it - they are most likely just branding third party stuff; and if you look at reviews, many of their so slightly modified things just happen to have a lot of issues). I wish they would just make honest marketing and sell stuff that works painfree.
 

Yurii Suhov

macrumors newbie
Aug 8, 2019
4
2
Those are exactly the modules I installed in my machine (4 of them) - they work just perfectly.

Also, I never had a problem with Samsung memory modules. But you do find quite a number of faulty OWC modules here in the forums. I honestly think most of the OWC stuff is highly overrated (they offer a great range of products, but - let's face it - they are most likely just branding third party stuff; and if you look at reviews, many of their so slightly modified things just happen to have a lot of issues). I wish they would just make honest marketing and sell stuff that works painfree.
Thanks for your quick reply here!
Ill be good with 2x32 + stock 8gb at the start? Heard that it gave some kernel panics in that configuration.
 

whosthis

macrumors member
Aug 21, 2008
99
44
I cannot help on that part, but I remember a thread with some issues regarding mixing single and double sided.
But chances are the 8 GB are not that much of an improvement over the 64 GB for most users, compared to adding just 2x8 GB or so. So if it makes problems, throw them out.
RAM is luckily pretty affordable at the moment. The cool thing I can do with 128 GB is to create a 32 GB RAMDisk, clone a fresh OS X virtual machine onto it, run it from there with 32 GB RAM and a couple of cores, mess around with it, and dispose it without tripping the SSD or worrying about anything else running. I just start to enjoy not needing to install some legacy (or crappy) tools on the production machine directly. :)
 

Yurii Suhov

macrumors newbie
Aug 8, 2019
4
2
I cannot help on that part, but I remember a thread with some issues regarding mixing single and double sided.
But chances are the 8 GB are not that much of an improvement over the 64 GB for most users, compared to adding just 2x8 GB or so. So if it makes problems, throw them out.
RAM is luckily pretty affordable at the moment. The cool thing I can do with 128 GB is to create a 32 GB RAMDisk, clone a fresh OS X virtual machine onto it, run it from there with 32 GB RAM and a couple of cores, mess around with it, and dispose it without tripping the SSD or worrying about anything else running. I just start to enjoy not needing to install some legacy (or crappy) tools on the production machine directly. :)
Thanks!
Actually, if you take a look at Jeffs Benjamins video where he upgrades his iMac with OWC 128GB kit, it clearly says that those are Samsung M471A4G43MB1-CTD sticks. https://9to5mac.com/2019/04/05/how-to-upgrade-27-inch-5k-imac-2019-128-gb-ram-video-tutorial/
So, you are right, they are just rebranding stuff and adding OWC tax on top of it...:D
 

priitv8

macrumors 601
Jan 13, 2011
4,028
638
Estonia
Hi guys, waiting for my i9 iMac to arrive soon, was thinking to go for a 64GB of total RAM, but I found these Samsung sticks which are very similar that OWC used, but costs a almost 2 times less, have anyone tried them?
https://www.scan.co.uk/products/32g...MItLzuyLnz4QIVy7ftCh1WFw6DEAQYASABEgJW1fD_BwE
Crucials are even cheaper
Crucial CT2K16G4SFD8266 32 GB Kit (16 GB x2) (DDR4, 2666 MT/s, PC4-21300, Dual Rank x8, SODIMM, 260-Pin) Memory https://www.amazon.co.uk/dp/B071H38422/
Mine came with Micron chips, same brand as apple stock modules.
 
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smayer97

macrumors member
May 24, 2010
56
10
I cannot help on that part, but I remember a thread with some issues regarding mixing single and double sided.
...

Not so sure this is a problem... MANy users here, including myself, installed doubled-sided RAM (in my case 2x16GB Crucial RAM) + original singled-sided 2x8GB RAM (SK-Hynix) with no issues. If some do have problems (I have not seen anyone report this in this thread), the problem may be more complex.
 
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smayer97

macrumors member
May 24, 2010
56
10
...
The cool thing I can do with 128 GB is to create a 32 GB RAMDisk, clone a fresh OS X virtual machine onto it, run it from there with 32 GB RAM and a couple of cores, mess around with it, and dispose it without tripping the SSD or worrying about anything else running. I just start to enjoy not needing to install some legacy (or crappy) tools on the production machine directly. :)

Just curious, how do you create your RAMDisk; terminal commands (I know how do to that) or some util? If the latter, does it have write-back functionality? I'm always in search of a good RAMDisk util but cannot find a current one that does this.
 

whosthis

macrumors member
Aug 21, 2008
99
44
Just curious, how do you create your RAMDisk; terminal commands (I know how do to that) or some util? If the latter, does it have write-back functionality? I'm always in search of a good RAMDisk util but cannot find a current one that does this.
At the moment I'm using the command line.

diskutil erasevolume HFS+ "RAMDisk" `hdiutil attach -nomount ram://16384000`​

(example for about 8 GB I think).

I had some tool installed in the past that would also mount the volumes for Xcode or Safari cache right onto it. But the speed gain is marginal there, and it comes with a couple of downsides.

So for real world code development, it doesn't pay off any more (at least compared with the super fast installed SSD).

Same holds true for a Mojave installation in a virtual machine. Takes 19 seconds to boot up from SSD, and exactly the same time from RamDisk (after a boot, so there should have been no caching).

Maybe APFS helps the SSD here, and I "only" used HFS+ for the RAM disk. I might try APFS on the RAM disk as well, just for fun.
 

smayer97

macrumors member
May 24, 2010
56
10
At the moment I'm using the command line.

diskutil erasevolume HFS+ "RAMDisk" `hdiutil attach -nomount ram://16384000`​

(example for about 8 GB I think).

I had some tool installed in the past that would also mount the volumes for Xcode or Safari cache right onto it. But the speed gain is marginal there, and it comes with a couple of downsides.

So for real world code development, it doesn't pay off any more (at least compared with the super fast installed SSD).

Same holds true for a Mojave installation in a virtual machine. Takes 19 seconds to boot up from SSD, and exactly the same time from RamDisk (after a boot, so there should have been no caching).

Maybe APFS helps the SSD here, and I "only" used HFS+ for the RAM disk. I might try APFS on the RAM disk as well, just for fun.

Typical block size is 2048 / MB, therefore 16384000/2048=8000 MB = 8GB (non-binary).

Other advantage of RAMDisk is reduced wear on SSD.

So yours are not persistent nor have write-back. Other than these, what other downsides have you encountered?

Thanks for the reply.
 

whosthis

macrumors member
Aug 21, 2008
99
44
Other advantage of RAMDisk is reduced wear on SSD.
Exactly. While it's probably an overrated issue for usual daily tasks, I think it may actually be worthwhile for a couple of things. The virtual machine example to test things is such a case for me; cloning to the RAMDisk of around 15 GB takes less than 10 seconds, and it gets disposed properly afterwards - so it cannot be forgotten on disk.
Maybe also a good idea for some heavy image work that still fits on the RAM.
So yours are not persistent nor have write-back. Other than these, what other downsides have you encountered?
No real other downsides I guess. For development, when you put the dev. folders on there, it basically does a clean build for every dependency on the first run, which may or not be what one wants. It just didn't bring any real advantage, so I stopped using it (persistence may solve some problems, but also look out for the size - when the disk is full it might behave unexpected). Non-persistent caching is also at least somewhat defeating the purpose of the cache, but that's all not new to you. :)
So I think its usefulness has dropped quite a bit, but it has its applications.
As I understand it, the OS uses free RAM for caching files anyway quite aggressively, which further minimizes its benefits (and might get in its way). And I'm not sure if the system will also cache files from the RAMDisk as well - I guess it probably will...
 
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