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Crazy idea. 32GB RAM modules in a cMP. Anyone tried this?

BjarneDM said:
I haven't had any issues with ♨️🔥 as far as I can tell 🙏🏻
Skærmbillede 2021-04-13 kl. 01.13.40.png
Click to expand...
AFAIK you're the first person that got the 32GB DIMMs working perfectly , kudos!
As mentioned by @RAMtheSSD too, i was curious about Temps .

Looking at the Temps , i wonder if the screenshot was taken at idle ?
Delta CPU A is 26degrees, delta CPU B is 16 degrees.
I would consider a repaste of the CPU heatsinks .

Delta NB is 15degrees , imo the limit , personally in case of a repaste CPUs, i would repaste the NB heatsink too , and (if not done already) replace the rivets.

DIMMs slot 1-4 are 55-59 degrees and much higher than slot 5-8 (41-44).
Although ambient T is 29degrees, this is IMO still high (if at idle) , but could be related to bad Delta CPU A.

PSU S2 ( the one that seems to heat up more depending on GPU powerdraw and CPU load ) is 66degrees.
The PSU fan is set to 600 (fixed i guess), i would recommend to set this fan depending on PSU supply 2 Temp or on default to avoid further decreasing expected life time of (especially the capacitors in) the PSU.

These are just some thoughts a bit off topic, but with best intentions :)
 
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My cMP is 🤓always🤓 running at 💯 CPU as I'm contributing to both
They both throttle down when other processes needs the CPUs
As to the fans, I haven't messed around with any settings at all.

Skærmbillede 2021-04-13 kl. 15.31.19.png
As to the CPU 🌡 I had been wondering about the differences & had considered a re-paste ; but being unsure about my own skills in that regard, I've held off doing it. I bought my cMP from a reseller in 🇬🇧 w/ the CPU upgrade installed.

@KeesMacPro : Thanks for the kudos 👍🏻🤓
But the real kudos should go to @h9826790 for his work in https://forums.macrumors.com/thread...n.2180095/page-53?post=28255048#post-28255048 and the OpenCore team 🤓👍🏻 I've just used some 💰💸
 
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VitaminK said:
R4x4 dimms should be running at 1066mhz in a Mac Pro correct?
Click to expand...
in short : No

The 🤓🤔complicated🤔🤓 answer:

A memory stick has a base frequency & a motherboard has a base frequency for the memory.
You can install memory both faster and slower than the motherboard memory frequency. Faster does nothing for the performance; slower reduces performance.

A memory stick and the motherboard has a DDR specification. For cMP it's DDR3; for modernMP it's DDR4. This means that you get the best performance if-and-only-if you install the memory 3 banks at a time; thus for a cMP this will be: 48 GB ; 96 GB ; 192 GB . Installing more -or- less will negatively influence you memory speed. Then why go higher; ie in my case 256 GB? because I need the memory capacity for VMs and they are memory hungry; speed isn't that much of an issue here. On the other hand, if your workload is VideoEditing, then stay with 48 GB -or- 96 GB Unbuffered.

A memory stick also has a type : Unbuffered, Registered, LoadReduced.
For Registered and LoadReduced, there's a cost of 1 CPU cycle for each memory access, thus Unbuffered is marginally faster than Registered and LoadReduced; that's why I didn't include 192 GB in the VideoEditing recommandation. The advantage w/ Registed & LoadReduced is, that these types lower the load on the memory controller and makes it possible for the CPU to handle more RAM.

So, in order to benchmark a cMP you'll have to test 4 memory configurations : 48/96 GB & 64/128 GB Unbuffered; 96/192 GB & 128/256 GB Registered.

Personally, I'm presently not willing to engage in this.
 
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i need some help from you experts:

I have a 4,1>5,1 dual X5550 2.66, it came with 4x 2Gb sticks and booted up fine.

Now I am trying to use some known good 32Gb ram sticks that I already have (tested on other machine) but they are 1866mhz Samsung (M386B4G70DM0-CMA4) and they dont work on this 4,1>5,1. I read @edgerider in post #138https://forums.macrumors.com/thread...a-cmp-anyone-tried-this.2046693/post-27562852
that samsung 1866 should work?

Test1: 4x 2Gb + 1x 32Gb: El Capitan booted up OK and recognized only the 4x2Gb = 8Gb. The slot where I put 32Gb will show empty.

Test2: 1x 32Gb: machine turn on with blinking power led

Test3: 8x 32Gb: machine turn on with blinking power led

Test4: 3x 2Gb + 1x 32Gb: recognize only the 6Gb.

Any idea?
 
protocold said:
i need some help from you experts:

I have a 4,1>5,1 dual X5550 2.66, it came with 4x 2Gb sticks and booted up fine.

Now I am trying to use some known good 32Gb ram sticks that I already have (tested on other machine) but they are 1866mhz Samsung (M386B4G70DM0-CMA4) and they dont work on this 4,1>5,1. I read @edgerider in post #138https://forums.macrumors.com/thread...a-cmp-anyone-tried-this.2046693/post-27562852
that samsung 1866 should work?

Test1: 4x 2Gb + 1x 32Gb: El Capitan booted up OK and recognized only the 4x2Gb = 8Gb. The slot where I put 32Gb will show empty.

Test2: 1x 32Gb: machine turn on with blinking power led

Test3: 8x 32Gb: machine turn on with blinking power led

Test4: 3x 2Gb + 1x 32Gb: recognize only the 6Gb.

Any idea?
Click to expand...
woah it was a long time ago in my xserve and with 16gb if I recal correctly (dont quote me on this) dont think the issue is the frequency here, as stated below if you want to go over 16gb per stick, you need to use a trick to let the machine know what it is because it only knows 16gb stick...
remenber that back in the day 32 gb didnt exist, let alone that 16gb where like a grand pièce...
 
But from recent developments on this thread (see above), others are able to boot up with 32Gb sticks..

Kon_Kipa can get 160Gb working with a 4,1>5,1 so a flashed 4,1 should not be the issue.

I wonder if the problems come from:
A) my CPU: Can X5550 support these? But if Kon_Kipa can get 32Gb stick working with his E5520, then I suppose the X5550 can do so too?
B) The ram type and timing? Is there a way to change the timing on the SPD on these sticks?
 
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no go.. i tested in linux:
1)with only 32Gb stick (whether single or 2 of a few), machine only have led blinks
2)with 3x2Gb + 1x32Gb stick, machine booted up but Linux only see 6Gb....

I suspect it is the ram and they are too fast and dont support lower speed in SPD table?

@BjarneDM when you have full 8x32Gb in there.. what is the clock speed of the memory?!
 
@protocold
When comparing your and my memory sticks, we have :
memory.net

M386B4G70DM0-CMA - Samsung 1x 32GB DDR3-1866 LRDIMM PC3-14900L Quad Rank x4 Module

Get ➡️ Lifetime warranty ✅ Great savings ✅ Buy factory original M386B4G70DM0-CMA - Samsung 1x 32GB DDR3-1866 LRDIMM PC3-14900L Quad Rank x4 Modules @Memory.NET!
memory.net memory.net
memory.net

HMT84GR7MMR4A-H9 - SK Hynix 1x 32GB DDR3-1333 RDIMM PC3L-10600R Quad Rank x4 Module

Get ➡️ Lifetime warranty ✅ Great savings ✅ Buy factory original HMT84GR7MMR4A-H9 - SK Hynix 1x 32GB DDR3-1333 RDIMM PC3L-10600R Quad Rank x4 Modules @Memory.NET!
memory.net memory.net
there're two differences :
  1. clock speed : 1866 <-> 1333
  2. type : lrdimm <-> rdimm
(1) ought not to be an issue : https://www.ifixit.com/Answers/View/528682/Can+I+use+PC3L+12800S+RAM+in+place+of+PC3+10600S+RAM
(2) this is the issue as far as I can see : from https://en.wikipedia.org/wiki/Registered_memory "Both FB-DIMMs and LR-DIMMs are designed primarily to minimize the load that a memory module presents to the memory bus. They are not compatible with R-DIMMs, and motherboards that require them usually will not accept any other kind of memory modules."

The motherboard in a cMB can accept -either- ddr3 udimm -or- ddr3 rdimm. 16GB sticks exist in both specifications; 32GB only in rdimm. You can't mix udimm & rdimm. & it looks as if 32GB is the max size for rdimm - higher capacity is lrdimm.

The clock speed of the memory in my cMP is 1333 because that's the specification of both the motherboard & the memory sticks. Generally, the memory will run at the minimum of the clock specification of the motherboard and the memory sticks.

But whether it's (1) -or- (2) is irrelevant : if Linux can't see the sticks & you've also got red lights on the motherboard - the 32 GB lrdim's you've got don't work in a cMP 👎🏻

On the other hand you've saved me some 💰 as my next experiment would have been to try 64 GB lrdimms. If your 32 GB lrdimms don't work, then 64 GB lrdimms also won't work 🤓😢😭

🤓🤔 in conclusion :
In a cMP the max memory is 256 GB using 8 x 32 GB 4x4 ecc rdimm
 
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no i didnt buy them, i already have them and they dont boot up at 1333 but only 1066.... how come?!?!
 
how many of them have you installed ? The optimal is three sticks @ cpu
how are you measuring the memory MHz ?
for certain configurations, the memory speed is 1066MHz
 
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protocold said:
only 2 and i saw it said 1066 under About this Mac->System Report->Memory.
Click to expand...
That's a sub-optimal configuration 🤔👎🏻
Try w/ 3 equal sticks per cpu which is the optimal configuarion.
OpenCore seems to mess up w/ the Mac System Report & ‼️always‼️ reports the OpenCore configuration 🤔

Did some futher research :
en.wikipedia.org

Mac Pro - Wikipedia

en.wikipedia.org en.wikipedia.org
the 2009 and onward Mac Pro use 1066 MHz DDR3 ECC DIMMs for the standard models, and 1333 MHz DDR3 ECC DIMMs for systems configured with 2.66 GHz or faster CPUs

Mac Pro (Mid 2010) - Technical Specifications - Apple Support

support.apple.com support.apple.com
Memory
  • Dual-processor systems
    • 2.4GHz system: 1066MHz DDR3 ECC SDRAM
    • 2.66GHz and 2.93GHz systems: 1333MHz DDR3 ECC SDRAM
  • Single-processor systems
    • 2.8GHz and 3.2GHz systems: 1066MHz DDR3 ECC SDRAM
    • 3.33GHz system: 1333MHz DDR3 ECC SDRAM

Mac Pro (Mid 2012) - Technical Specifications - Apple Support

support.apple.com support.apple.com

Memory​

  • Dual-processor systems
    • 2.4GHz, 2.66GHz, and 3.06GHz systems: 1333MHz DDR3 ECC SDRAM
  • Single-processor systems
    • 3.2GHz system: 1066MHz DDR3 ECC SDRAM
    • 3.33GHz system: 1333MHz DDR3 ECC SDRAM
@protocold what's your cpu configuration ❓
 
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ok they are here... I havent done the opencore part yet but the machine recognized 6 sticks under Linux. El Capitan wont boot.

Question: Do I really have to remove the lid cap of the CPU before install?
 
protocold said:
ok they are here... I havent done the opencore part yet but the machine recognized 6 sticks under Linux. El Capitan wont boot.
Click to expand...
That's normal : Linux can see 32GB sticks out-of-the-box ; macOS is only able to see 16GB sticks before OpenCore and thus completely refuses to boot.

protocold said:
Question: Do I really have to remove the lid cap of the CPU before install?
Click to expand...
on this page : https://everymac.com/systems/apple/...-2010-westmere-how-to-upgrade-processors.html they write :
However, on the "Mid-2010" and "Mid-2012" Mac Pro models, Apple uses standard processors rather than ones that lack a "lid" like their predecessors.
Click to expand...
And in this video : https://duckduckgo.com/?kl=us-en&q=upgrade+cpu+macpro+2010+2012&t=seamonkey&iax=videos&ia=videos&iai=https://www.youtube.com/watch?v=KpcMAXjJLhg one can see he hasn't delidded the CPUs & he also doesn't mention that he has
 
protocold said:
I have a 4,1>5,1 dual X5550 2.66
Click to expand...

protocold said:
Do I really have to remove the lid cap of the CPU before install?
Click to expand...
Yes, it's recommended to install delidded CPUs.

It is possible to install the "normal" lidded CPus but there's a serious risk of damaging the CPU sockets.

Here's some more info post #1:
forums.macrumors.com

Mac Pro CPU Compatibility List

Bokkow and I have created a Mac Pro CPU compatibility list. The intent is to cover all relevant and compatible CPU upgrades for all Mac Pros. These are asked about over and over and over again, so I thought it would be nice to have it all in one place. Constructive criticism, corrections to...
forums.macrumors.com forums.macrumors.com
 
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protocold said:
Question: Do I really have to remove the lid cap of the CPU before install?
Click to expand...

like @KeesMacPro suggests, take time to do research and be well informed before jumping into installing lidded CPUs in a 4,1. probability of damaging sockets and more is very high. lots of threads cover the risks and walk you through best practices.
 
I have tried it. macOS does not boot with even 1 32gb RAM stick but the memory works fine in Windows 10. You need Pro to get >128GB of RAM to be recognized. The memory is 4Rx4 so it only runs at 1066mhz in a Mac Pro.
 
okay.. i will take the time to research as there is no hurry in upgrading the CPU.

I will probably try to get OpenCore to work with MacOS first and then figure out the CPU lid problem later...
 
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