MP 7,1 Which LRDIMM 2933 64GB RAM for 2019 Mac Pro - Samsung vs Micron vs Hynix?

paulchiu

macrumors member
Original poster
Feb 26, 2009
77
31
nyc
Has anyone upgraded to LRDIMM 64GB 2933 chips with ones from Samsung, Micron or Hynix?

1. M386A8K40CM2-CVF Samsung 64GB PC4-23400 DDR4-2933MHz ECC https://www.memory4less.com/samsung-server-memory-m386a8k40cm2-cvf

2. HMAA8GL7CPR4N-WM Hynix 64GB PC4-23400 DDR4-2933MHz ECC https://www.memory4less.com/hynix-server-memory-hmaa8gl7cpr4n-wm

3. MTA72ASS8G72LZ-2G9 Micron 64GB PC4-23400 DDR4-2933MHz ECC https://www.memory4less.com/micron-64gb-ddr4-pc23400-mta72ass8g72lz-2g9

All three now at the same price of $299.43

I read Apple may be using Micron but are the Samsung more reliable? Are all three pretty much the same speeds?

Thanks!

Paul
 

Alpaone

macrumors newbie
Dec 20, 2019
3
4
There is no speed difference between the modules as they all use the same timings.

M386A8K40CM2-CVF uses Samsung 8Gb C-Dies (1x nm)

MTA72ASS8G72LZ-2G9 uses Micron 8Gb D-Dies (20 nm)

HMAA8GL7CPR4N-WM uses SK hynix 8Gb C-Dies (18nm)

Those Samsung / SK Hynix DIMMs should use slightly less power and remain cooler thanks to their smaller fabrication process.
 
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paulchiu

macrumors member
Original poster
Feb 26, 2009
77
31
nyc
There is no speed difference between the modules as they all use the same timings.

M386A8K40CM2-CVF uses Samsung 8Gb C-Dies (1x nm)

MTA72ASS8G72LZ-2G9 uses Micron 8Gb D-Dies (20 nm)

HMAA8GL7CPR4N-WM uses SK hynix 8Gb C-Dies (18nm)

Those Samsung / SK Hynix DIMMs should use slightly less power and remain cooler thanks to their smaller fabrication process.

Thanks!
I will be ordering the Samsung then.
Just got notice that my Mac Pro shipped today.

Paul
 
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kittiyut

macrumors 6502
Oct 28, 2007
266
9
Interesting!

How are those Samsung modules compared to the ones offered by OWC @ $2,549.99 for 6x64GB?

Why such a price difference???!!!
 
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Snow Tiger

macrumors 6502
Dec 18, 2019
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They appear to entirely be identical . I'd personally go with Sammy as a System Builder and a former Macintosh memory module manufacturer I know also recommends the same .
 
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kittiyut

macrumors 6502
Oct 28, 2007
266
9
avoid micron at all costs.. the quality can be terrible. ive had a number of boxes have trouble with it in the past
samsung and hynix are solid though.
Would you go with Sammy instead of OWC to save $$$ ???

Also, is memory4less a reputable seller?
 

paulchiu

macrumors member
Original poster
Feb 26, 2009
77
31
nyc
Ended up ordering from memory.net on the 64GB 2933 for 288 on 12.
Will arrive Wed the 8th. They offered 2 day air free.
 
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tomatomic

macrumors newbie
Jan 6, 2020
4
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Los Angeles, CA
Would you go with Sammy instead of OWC to save $$$ ???

Also, is memory4less a reputable seller?
Id absolutely go with samsung.. if thats what you mean by sammy ;-)
i used to have a small studio with about 20 macs..micron underperformed and I ran into faulty dimms.
samsung has been the absolute best. I usually look up which manufacturer memory is made by.. (OWC does not make their own memory - they are reliable in my experience, but i usually go to the source and save some cash.

i have trusted crucial, but they seem to use micron now.. so.. twice burned thrice shy..
 
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Alpaone

macrumors newbie
Dec 20, 2019
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AidenShaw

macrumors P6
Feb 8, 2003
18,410
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The Peninsula
i have trusted crucial, but they seem to use micron now..
Crucial is Micron's storefront, and has been for decades.

Crucial — The memory and storage experts.™

As a brand of Micron, one of the largest memory manufacturers in the world,
 
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paulchiu

macrumors member
Original poster
Feb 26, 2009
77
31
nyc
Samsung C-Die is 1x-nm. Samsung D-Die is newer 1y-nm.



Samsung DDR4-3200 CL=22 DIMMS will just downclock to DDR4-2933 CL=21.

If you want any Dies better than Samsung D-Die, you would have to go for 16Gb A-Dies, as those are fabricated in 1z-nm.
Following you there, I noticed two part numbers: M386A8K40CM2‐CVF and M386A8K40DM2‐CVF the difference being "C" vs "D"

Any difference? And why not use the faster DDR4-3200?
I thought about the 3200 rated speed but did not know how to modify my Mac Pro in order to take advantage of it.
 

Snow Tiger

macrumors 6502
Dec 18, 2019
357
217
The RAM arrived.
The Mac Pro should arrive tomorrow.
Is there some RAM testing program I should run?

View attachment 887568


View attachment 887569
Memtest for Mac . But it will take a long time with a 768 GB ( 12 x 64 GB ) memory kit .

I hope the program is 64 bit ... so it runs on Catalina . I actually don't know offhand . 32 bit programs do not run in this OS .
- - Post merged: - -
 
Last edited:

paulchiu

macrumors member
Original poster
Feb 26, 2009
77
31
nyc
Memtest for Mac . But it will take a long time with a 768 GB ( 12 x 64 GB ) memory kit .

I hope the program is 64 bit ... so it runs on Catalina . I actually don't know offhand . 32 bit programs do not run in this OS .
- - Post merged: - -
Are we talking about hours & days? Is there a faster way to test?
 

Snow Tiger

macrumors 6502
Dec 18, 2019
357
217
Are we talking about hours & days? Is there a faster way to test?
In a cMP , this test will take between 12 to 24 hours to run with a 128 GB ( 8 x 16 GB ) configuration .
- - Post merged: - -

You might want to use another program , as Memtest for Mac will not run in Mojave . I just tried .

It runs fine with some earlier macOSes , but you can't run them in a MP7,1 .
 

konqerror

macrumors 65816
Dec 31, 2013
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2,234
I've been using both Samsung and Micron RAM for decades (with the odd few sticks of Hynix here and there), and never had a single failure in any of them. I wouldn't overthink this.
I've had specific issues with Micron RAM causing random freezing in several Skylake SP systems. We replaced all Micron with Samsung, which was the OEM choice, and the problems went away.

In fact, Rowhammer-type corruption was demonstrated on Micron DDR4, but not Samsung, RAM.
 
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paulchiu

macrumors member
Original poster
Feb 26, 2009
77
31
nyc
In a cMP , this test will take between 12 to 24 hours to run with a 128 GB ( 8 x 16 GB ) configuration .
- - Post merged: - -

You might want to use another program , as Memtest for Mac will not run in Mojave . I just tried .

It runs fine with some earlier macOSes , but you can't run them in a MP7,1 .

I think I will just run GeekBench 5 with the 32GB factory and then with the 768GB.
Heavy computations and use over the next 2 weeks should tell me if the RAM is good.
- - Post merged: - -

In a cMP , this test will take between 12 to 24 hours to run with a 128 GB ( 8 x 16 GB ) configuration .
- - Post merged: - -

You might want to use another program , as Memtest for Mac will not run in Mojave . I just tried .

It runs fine with some earlier macOSes , but you can't run them in a MP7,1 .

I think I will just run GeekBench 5 with the 32GB factory and then with the 768GB.
Heavy computations and use over the next 2 weeks should tell me if the RAM is good.