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abdyfranco

macrumors regular
Dec 4, 2017
126
120
Does anyone know if it is possible to use 8x32GB DIMMs on a dual processor Mac Pro to get 256GB of RAM?
 

ActionableMango

macrumors G3
Sep 21, 2010
9,606
6,872
There was a firmware update for High Sierra. Although I highly doubt that update would have changed the memory capacity of the Mac Pro, if anyone happens to have the RAM to spare for a test it might be worth checking.
 

h9826790

macrumors P6
Apr 3, 2014
15,393
7,668
Hong Kong
This non ECC UDIMM can also be used in cMP. I actually used these DIMMs for few years.

ADATA AD3U1600W8G11-B

It is a 1600MHz DIMM. However, for this DIMM, if running 3x8GB, the RAM can run at 1333MHz without issue. But if install them in all 4 slots, the clock speed will be automatically reduced to 1066MHz. This DIMM also has life time warranty provided by ADATA.
8GB UDIMM.JPG
 

dolphin842

macrumors 65816
Jul 14, 2004
1,172
29
I've been using 3 x 16GB Kingston 1333MHz RDIMMs (model KVR13R9D4/16) in my 6-core 5,1 for several years without issue.

One question I had was... would these modules work in a 2013 nMP 6,1 as well?
 

bsbeamer

macrumors 601
Sep 19, 2012
4,078
2,179
I've been using 3 x 16GB Kingston 1333MHz RDIMMs (model KVR13R9D4/16) in my 6-core 5,1 for several years without issue.

One question I had was... would these modules work in a 2013 nMP 6,1 as well?

Currently have three of those same 16GB RAM modules in a 5,1 6-core tray. They are 1333MHz DDR3 PC3-10600 ECC Registered CL9 240-Pin.

The 6,1 Mac Pro DIMMs are rated for 1866MHz DDR3 ECC. (Believe PC-14900.)
https://support.apple.com/en-us/HT202892

Believe the 32GB modules are capped at 1333MHz in the MacPro6,1. Know people who are using four of them (128GB total) currently in their 6,1 machines. Unsure if you'd "need" to add a 4th module, but they should work.
 

MarkJames68

macrumors 6502
Sep 24, 2017
394
246
Currently have three of those same 16GB RAM modules in a 5,1 6-core tray. They are 1333MHz DDR3 PC3-10600 ECC Registered CL9 240-Pin.

The 6,1 Mac Pro DIMMs are rated for 1866MHz DDR3 ECC. (Believe PC-14900.)
https://support.apple.com/en-us/HT202892

Believe the 32GB modules are capped at 1333MHz in the MacPro6,1. Know people who are using four of them (128GB total) currently in their 6,1 machines. Unsure if you'd "need" to add a 4th module, but they should work.
I believe the speed also depends on the CPU. 4 and 6 core are 1333 but lower speed for 8 and 12.
 
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flowrider

macrumors 604
Nov 23, 2012
6,766
2,627
Speed depends on BOTH the CPU and the DIMM. The CPU usually has a RAM rating of two or three speeds, a DIMM rated at a speed faster than one the CPU will run at, will clock down. OTOH, a DIMM has one speed rating, but will clock down depending on the rating of the CPU.

Lou
 

ActionableMango

macrumors G3
Sep 21, 2010
9,606
6,872
This thread title and post are a bit mixed up. In the title, "cMP & nMP" would be 1,1 through 6,1. It then says "4,1 & 5,1" which are cMP only and not nMP. Then the actual post itself seems to be 5,1 only.
 

NATO Potato

macrumors newbie
Jan 18, 2018
1
0
Apple Ram, Shmapple RAM, doesn't matter. It's the RAM specs that matter. Apple doesn't make and has never made RAM, they buy it just like you or me, but for a much lower price of course!

Lou
[doublepost=1515193928][/doublepost]

I've read of problems with that configuration. The problem is associated with the CPUs in the cMP 4,1 and 5,1 having three memory channels. In Apples configuration the third and fourth channel are physically tied together. Have you tried filling only three slots (slots 1 thru 3) and leaving slot 4 MT? If not, give it a try. If that works and 48GBs is not enough for you, I've heard that putting a smaller DIMM (8GB) in slot 4 may work.

Lou


This thread is kind of what I'm struggling with right now. I want to run 48g, in 4x4 and 4x8 configuration in a 4.1 I have recently had intermittent problems with RAM slot 1 not reading, and have done a fair amount of troubleshooting, short of cleaning the contacts. Any suggestions would be appreciated. Heres what's reading now.
upload_2018-5-7_14-21-51.png
 
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willhay555

macrumors newbie
May 14, 2018
2
0
Leeds, UK
Hello there.
First time poster here in the UK with limited technical knowledge, just upgrading from a 2014 13" MBP i5 2.6Ghz.

I've just picked up a cMP 2010 QC 2.8Ghz with stock ITB SATA and a 5770.

I'm already adding a couple of SSD's, the PCIe usb 3.0 card is in and I'm waiting for the 6C 3.46G to arrive.

All I want to do now is use that last memory bay.

I already have x3 8GB Kingston 1333 *ECC* which, if I've done my research is running at 1066 due to my 4C processor.

My question is simply this; if I use non-ECC memory in the fourth bay will I see anything detrimental to what will be 32GB RAM?

Thanks.
 
Last edited:

MarkJames68

macrumors 6502
Sep 24, 2017
394
246
Hello there.
First time poster here in the UK with limited technical knowledge, just upgrading from a 2014 13" MBP i5 2.6Ghz.

I've just picked up a cMP 2010 QC 2.8Ghz with stock ITB SATA and a 5770.

I'm already adding a couple of SSD's, the PCIe usb 3.0 card is in and I'm waiting for the 6C 3.46G to arrive.

All I want to do now is use that last memory bay.

I already have x3 8GB Kingston 1333 *ECC* which, if I've done my research is running at 1066 due to my 4C processor.

My question is simply this; if I use non-ECC memory in the fourth bay will I see anything detrimental to what will be 32GB RAM?

Thanks.
You can’t mix and match.
 

h9826790

macrumors P6
Apr 3, 2014
15,393
7,668
Hong Kong
Hello there.
First time poster here in the UK with limited technical knowledge, just upgrading from a 2014 13" MBP i5 2.6Ghz.

I've just picked up a cMP 2010 QC 2.8Ghz with stock ITB SATA and a 5770.

I'm already adding a couple of SSD's, the PCIe usb 3.0 card is in and I'm waiting for the 6C 3.46G to arrive.

All I want to do now is use that last memory bay.

I already have x3 8GB Kingston 1333 *ECC* which, if I've done my research is running at 1066 due to my 4C processor.

My question is simply this; if I use non-ECC memory in the fourth bay will I see anything detrimental to what will be 32GB RAM?

Thanks.

YES, all ECC will be disabled.

HOWEVER, you MUST make sure they are either ALL UDIMM or ALL RDIMM. You can't mix them together.

You can’t mix and match.

WRONG, I already proved that we can mix ECC with non ECC, different capacity, and different speed DIMM together.

https://forums.macrumors.com/threads/can-i-mix-memory-size.1903411/#post-21638766
 
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MarkJames68

macrumors 6502
Sep 24, 2017
394
246
YES, all ECC will be disabled.

HOWEVER, you MUST make sure they are either ALL UDIMM or ALL RDIMM. You can't mix them together.



WRONG, I already proved that we can mix ECC with non ECC, different capacity, and different speed DIMM together.

https://forums.macrumors.com/threads/can-i-mix-memory-size.1903411/#post-21638766
Thanks for clarifying. I was always aware of capacity and speed, but not ECC. I still think putting non-ECC kind of defeats the purpose, especially with the cheap prices nowadays.
 

willhay555

macrumors newbie
May 14, 2018
2
0
Leeds, UK
YES, all ECC will be disabled.

HOWEVER, you MUST make sure they are either ALL UDIMM or ALL RDIMM. You can't mix them together.

Thanks.
Will I see any loss of performance?

WRONG, I already proved that we can mix ECC with non ECC, different capacity, and different speed DIMM together.

https://forums.macrumors.com/threads/can-i-mix-memory-size.1903411/#post-21638766

Yeah, I saw that in the sticky :)

I asked because I'm struggling a little to find ECC 8GB for a reasonable price in the UK
 

vintagealuminum

macrumors newbie
Apr 23, 2018
8
2
actually i have mac pro 5.1 (4.1 flashed) Boot ROM Version MP51.0085.B00


i tried to add 2 x 32GB DDR3 4Rx4 to have 160GB ram,

but the mac pro don't like the 32GB sticks in any configuration.

slot 1 32GB
slot 5 32GB

mac pro don't start...no chime

slot 1 32GB
slot 2 16GB

slot 5 32GB
slot 6 16GB

mac pro start up with no problems, but it shows empty slots in slot 1 and 5 and total memory is only 32GB.

but somewhere mac pro see the 2 x 32GB sticks in slot 1 and 5 because

the total memory is downgraded from 1333mhz to 1066mhz speed.

usually i have 128GB ram running at 1333mhz.

if you have any idea why theses 32GB sticks
are not visible, thank you for your help and comments.

i resetted PRAM after intalling 32GB sticks,

thank you.
photo 1.JPG
photo 2.JPG
photo 3.JPG
View attachment 762734
 
Last edited:

handheldgames

macrumors 68000
Apr 4, 2009
1,795
1,057
Pacific NW, USA
actually i have mac pro 5.1 (4.1 flashed) Boot ROM Version MP51.0085.B00
please see "about this mac"


i tried to add 2 x 32GB DDR3 4Rx4 to have 160GB ram,

but the mac pro don't like the 32GB sticks in any configuration.

slot 1 32GB
slot 5 32GB

mac pro don't start...no chime

slot 1 32GB
slot 2 16GB

slot 5 32GB
slot 6 16GB

mac pro start up with no problems, but it shows empty slots in slot 1 and 5 and total memory is only 32GB.

but somewhere mac pro see the 2 x 32GB sticks in slot 1 and 5 because

the total memory is downgraded from 1333mhz to 1066mhz speed.

usually i have 128GB ram running at 1333mhz.

voila my tests, if you have any idea why theses 32GB sticks
are not visible, thank you for your help and comments.

i resetted PRAM after intalling 32GB sticks,

thank you.
View attachment 762731 View attachment 762732 View attachment 762733 View attachment 762734

The ram shown in the pic is a R4x4 32gb part. AFAIK... The 4,1/5,1 is compatible with R2x4 ddr3 RAM.

I’m currently running R2x4 16x16x16x8 with a 990x on a 4,1 flashed to 5,1
 

mani girafe

macrumors member
Aug 12, 2016
49
10
FRANCE
Here is the start to a mega thread of memory upgrades and FAQ

Please feel free to post your working configurations along with your brand and model numbers.


A single W36xx CPU can support up to 56GB memory (3x16 + 8)
A single X56xx CPU can support up to 64GB memory (4x16)
A dual X56xx CPU can support up to 160GB memory (5x32)

**Currently there is NO confirmation if 32GB DIMMs can be used on a single processor cMP to further push up the memory size limit.**


Apple's Recommendation:
  • PC3-10600E, 1333 MHz, DDR3 SDRAM UDIMMs
  • Error-correcting code (ECC)
  • 72-bit wide, 240-pin ECC modules
  • 36 ICs maximum per ECC UDIMM

The Mac Pro can accept slower memory. It just run slower.

The Mac Pro can accept faster memory, the DIMM will be automatically downclock to match the CPU / logicboard's max possible speed.

There is NO requirement to use ECC RAM on the cMP.

Memory specifications differ between 4,1 and 5,1

DIMM Supported Model Numbers (cMP 5,1)
- Users have reported that normal non-ECC DIMMs will work
<links and additional info needed>

UDIMM Supported Model Numbers (cMP 5,1)
- Apple's recommended RAM spec
Where to buy:
MacSales
eBay
Newegg
Amazon

Brands and Model Numbers:
Crucial
CT8G3W186DM
CT16G3W186DM

Kingston

Samsung
M391B5273CH0-CH9

Hynix

ELPIDA
RDIMM Supported Model Numbers (cMP 5,1)
- Yes RDIMMs work but you cannot mix with UDIMMs
- Perfomance differential is nominal

Where to buy:
eBay
Amazon
Newegg

Brands and Model Numbers:
Hynix
-- 8GB --
HMT31GR7BFR4C-H9 D7 AB

Samsung
-- 8GB --
M393B1K70CH0-CH9

Micron
-- 8GB --
MT36JSZF1G72PZ-1G4D1DD
-- 16GB --
MT36KSF2G72PZ-1G4

ELPIDA
-- 8GB --
EBJ81RF4ECFA-DJ-F​

32 gigas Ram with one CPU ( Mac pro 4.1) not flashed = no trouble
Memory :
Samsung 8GB 2Rx4 PC3L-10600R-09-10-E1-D2 -> M393B1K70CH0-YH9
 
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KXB17

macrumors newbie
Jul 10, 2018
10
2
Maitland, NSW, Australia
I'm hesitating on pulling the trigger on a RAM upgrade and this thread seems most likely to know the answer.

I literally just registered to ask my first (and probably last) question, so thanks to all in advance.

Also apologies in advance to any Moderators I may have annoyed if this is the wrong place to ask the question, but (see above) I almost certainly won't do it again :)

I have a single CPU 2010 cMP 5,1. Nothing like some of the monsters I'm seeing on here, but setup is (albeit in progress):

1 x CPU x5690, 1 x GPU Radeon RX580, 2 x PCIe 6GSSD and PCIe USB 3 Card. That's the basics anyway.

With a max upper limit of 64gb of 1333 ram in my configuration, can I use a 3 slot configuration of 1 x 32gb and 2 x 16gb

Is there actually a truly stable (if officially unsupported of course) 32GB module for a cMP 5,1.
As in a 32gb R2x4 ddr3 RAM, as mentioned above. I can't seem to easily search one at any rate.

FWIW my usage is 90% Logic Pro X (Home Studio, not pro), although for giggles I'm probably going to use it for a racing game or two. Think 'Need for Speed' here, not sim racing or the like. Also bear in mind that since the GPU supports it, I'm almost certainly going to try dabbling with a VR headset at some point soon as well.

I'm 48 and have ALWAYS maxed out RAM capabilities... we're talking since the mid-late 80's. Feel free to let me know whether or not that's still the necessary evil it used to be.

So for the first time in my life, I'm hoping for an answer along the lines of "Of course you can, you idiot newbie, didn't you read post blah blah blah, you goose!" :)

Hoping the answer helps other old fools like me reading this.

Thank you all again in advance.
 
Last edited:

mikas

macrumors 6502a
Sep 14, 2017
599
357
Finland
I believe you can do that, but why would you? (that's at least what I think I have read from threads here at MR)

That way you will lose triple channel bandwidth, versus with 3x16GB you get the ram cheaper AND get triple channel speed OR with 4x16GB you again lose triple channel, but the modules will be cheaper to buy versus 32GB+2x16GB.

If you own a 32GB stick already, then I understand the need for this.

I use 48GB in my single processor Mac Pros (4,1->5,1).
I once tried 56GB on a single proc (3x16GB+8GB), and I lost quite an amount of speed. So I took it back to 48GB.
(see attached pics, the same config exactly but the memory).
 

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handheldgames

macrumors 68000
Apr 4, 2009
1,795
1,057
Pacific NW, USA
I'm hesitating on pulling the trigger on a RAM upgrade and this thread seems most likely to know the answer.

I literally just registered to ask my first (and probably last) question, so thanks to all in advance.

Also apologies in advance to any Moderators I may have annoyed if this is the wrong place to ask the question, but (see above) I almost certainly won't do it again :)

I have a single CPU 2010 cMP 5,1. Nothing like some of the monsters I'm seeing on here, but setup is (albeit in progress):

1 x CPU x5690, 1 x GPU Radeon RX580, 2 x PCIe 6GSSD and PCIe USB 3 Card. That's the basics anyway.

With a max upper limit of 64gb of 1333 ram in my configuration, can I use a 3 slot configuration of 1 x 32gb and 2 x 16gb

Is there actually a truly stable (if officially unsupported of course) 32GB module for a cMP 5,1.
As in a 32gb R2x4 ddr3 RAM, as mentioned above. I can't seem to easily search one at any rate.

FWIW my usage is 90% Logic Pro X (Home Studio, not pro), although for giggles I'm probably going to use it for a racing game or two. Think 'Need for Speed' here, not sim racing or the like. Also bear in mind that since the GPU supports it, I'm almost certainly going to try dabbling with a VR headset at some point soon as well.

I'm 48 and have ALWAYS maxed out RAM capabilities... we're talking since the mid-late 80's. Feel free to let me know whether or not that's still the necessary evil it used to be.

So for the first time in my life, I'm hoping for an answer along the lines of "Of course you can, you idiot newbie, didn't you read post blah blah blah, you goose!" :)

Hoping the answer helps other old fools like me reading this.

Thank you all again in advance.

Some thoughts...

The x5690 is limited to 64GB with a single CPU.

A single CPU x5690, when paired with 2R4 RDIMMS should give you 64GB without slowdown: I'm running a 990x, the consumer version of the x5690 without ECC support, with 56GB @ 16x16x16x8 and have posted Geekbench 4 results showing 4 sticks is faster.

A Raid 0 ramdisk delivers 2x the 4k performance of today's best NVMe SSD's, elevating any workflow. Working without a SWAP/VM file also helps.

16GB Samsung 2r4 ECC RDIMMS can be found on ebay for $40/GB on a good day. Usually $50 each. RDIMMS cannot be mixed with non-RDIMMS.

So yes.... Of course you can. The Mac pro upgrade matrix is not a single path.
 
Last edited:

KXB17

macrumors newbie
Jul 10, 2018
10
2
Maitland, NSW, Australia
Some thoughts...

The x5690 is limited to 64GB with a single CPU.

A single CPU x5690, when paired with 2R4 RDIMMS should give you 64GB without slowdown: I'm running a 990x, the consumer version of the x5690 without ECC support, with 56GB @ 16x16x16x8 and have posted Geekbench 4 results showing 4 sticks is faster.

A Raid 0 ramdisk delivers 2x the 4k performance of today's best NVMe SSD's, elevating any workflow. Working without a SWAP/VM file also helps.

16GB Samsung 2r4 ECC RDIMMS can be found on ebay for $40/GB on a good day. Usually $50 each. RDIMMS cannot be mixed with non-RDIMMS.

So yes.... Of course you can. The Mac pro upgrade matrix is not a single path.
I believe you can do that, but why would you? (that's at least what I think I have read from threads here at MR)

That way you will lose triple channel bandwidth, versus with 3x16GB you get the ram cheaper AND get triple channel speed OR with 4x16GB you again lose triple channel, but the modules will be cheaper to buy versus 32GB+2x16GB.

If you own a 32GB stick already, then I understand the need for this.

I use 48GB in my single processor Mac Pros (4,1->5,1).
I once tried 56GB on a single proc (3x16GB+8GB), and I lost quite an amount of speed. So I took it back to 48GB.
(see attached pics, the same config exactly but the memory).
Thank you MIKAS, but this isn't what I'm suggesting/considering (unless I'm completely confused)
In short, single cpu @ x5690 allows 64gb ram max @ 1333mhz
General consensus seems to be 3 slot over 4 slot.
So I figure 32gb (Slot 1) + 16gb (Slot 2) + 16GB (Slot 3) = 64GB utilising the 3 slot architecture for speed.
I'm just not sure if there is a 32gb module that will work in this configuration.
[doublepost=1531266917][/doublepost]
Some thoughts...

The x5690 is limited to 64GB with a single CPU.

A single CPU x5690, when paired with 2R4 RDIMMS should give you 64GB without slowdown: I'm running a 990x, the consumer version of the x5690 without ECC support, with 56GB @ 16x16x16x8 and have posted Geekbench 4 results showing 4 sticks is faster.

A Raid 0 ramdisk delivers 2x the 4k performance of today's best NVMe SSD's, elevating any workflow. Working without a SWAP/VM file also helps.

16GB Samsung 2r4 ECC RDIMMS can be found on ebay for $40/GB on a good day. Usually $50 each. RDIMMS cannot be mixed with non-RDIMMS.

So yes.... Of course you can. The Mac pro upgrade matrix is not a single path.

Thank you Handheldgames, I'm actually using the RAM 0 method on the PCIe SSD's.

So what you're saying is 32gb (Slot 1) + 16gb (Slot 2) + 16GB (Slot 3) = 64GB would be no faster than 4 x 16GB?
 
Last edited:
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