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yurc

macrumors 6502a
Aug 12, 2016
818
973
inside your DSDT
Is also possible mapping larger RAM with OpenCore?

I was saw on Japanese blog able to successfully unsupported DIMMS configuration with Clover memory mapping.
 

VaZ

macrumors 6502
Aug 31, 2012
299
82
I wonder if HCDIMM will be seen at all by the MP5,1 .. or even any Mac with Sandy Bridge. There's not much documentation about this.
 

VaZ

macrumors 6502
Aug 31, 2012
299
82
im still waiting for someone to try a 64GB LR-DIMM or 8, for the LOLs :)
8Rx4 sticks now that's a whole different ballpark!
Anyone have any of these to test out?
s-l1600.jpg
 

kwikdeth

macrumors 65816
Feb 25, 2003
1,094
1,455
Tempe, AZ
this is really breaking my brain. I have worked in data centers for over 10 years and I have never seen or even heard of triple-rank memory before. This has got to be some obscure thing for some specific HP hardware. I cant find any listings of this RAM that arent related to HP machines. Even searching HP documentation comes up with basically nothing.

(edit) Found it. These are memory chips intended for HP 8th generation E5-4x00 blade servers and part of HP's "Smart Memory" line, whatever that means.
 
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BjarneDM

macrumors member
Jul 3, 2008
37
19
Korsør, Danmark, Europa
I bought these :
They've got 3 (three) models :
  • HMT84GR7BMR4A-H9
  • HMT84GR7MMR4A-H9
  • HMT84GR7AMR4A-H9
that according their support : All DRAM OEMs go through revisions in components used as time passes. They designate with slightly different part numbers. The specs are the same .

Alternatively , there's :
but they refused to sell to me due to my country and their current covid-19 shipping policies.

I've got some issues : I've got two red lights on 2 x 16 GB modules, so presently it seems as if these actually aren't seen. I'll do some more indepth experimentation. Currently I've got
  • 6 x 8 GB unregistered
  • 6 x 16 GB unregistered
  • 4 x 32 GB registed
in my posession, so I can mix and match rather freely. Until now, I've used dosdude1s patch with pleasure, and using those, I've been able to use 2 x ( 3 x 16 GB + 1 x 8 GB ) unregistered for a total of 112 GB without any issues.

I suppose my problem might be, that I've mixed 16 GB unregisterd & 32 GB registered modules which according to OWC is a no-go. Alternatively, it could be a problem with my specification of DDR3. If I understand things correctly, If you populate 3 memory slots / CPU cMP is using these as DDR3, but if you populate 4 memory slots / CPU cMP is using these as DDR2. I originally changed the setting from DDR4 to DDR3, so I'll have to take a look at what happens here.

What seems to happen is, that when you explicitly specify your RAM-configuration, macOS accept this as the gospel, !BUT! puts the RAM it actually can't see / isn't present into the wired memory category
Skærmbillede 2021-03-02 kl. 20.31.37.png
 
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BjarneDM

macrumors member
Jul 3, 2008
37
19
Korsør, Danmark, Europa
So, I've revised my setup:
  1. removed the 16 GB memory sticks
  2. revised the memory settings
I'm now getting this :
Skærmbillede 2021-03-02 kl. 22.18.31.png Skærmbillede 2021-03-02 kl. 22.18.48.png Skærmbillede 2021-03-02 kl. 22.18.53.png Skærmbillede 2021-03-02 kl. 22.19.07.png
Now, it's time to use this memory to the fullest to see if it actually works, so I'll open some memory intensive VirtualBox VMs
  • TrueNas 32 GB RAM ( used to test all apects of ZFS )
  • Catalina 16 GB RAM ( used to test advanced setup of users & ZFS & RAID5 )
  • Big Sur 16 GB RAM
  • Ubuntu 16 GB RAM ( used to test RAID5 & ZFS )
  • Windows Server 2019 ( 8 GB RAM )
(and: yes - I've doubled the RAM I'ld normally assign to most of them) which gives me : Skærmbillede 2021-03-02 kl. 23.36.56.png Skærmbillede 2021-03-02 kl. 23.37.03.png
So, now it's time to order 4 more 32 GB memory sticks ????
 

BjarneDM

macrumors member
Jul 3, 2008
37
19
Korsør, Danmark, Europa
8Rx4 sticks now that's a whole different ballpark!
Anyone have any of these to test out?
View attachment 919911
according to
the CPU can address 288 GB RAM, so if the board supports it, we can get to 384 GB with DDR3 and 512 GB with DDR2
 

BjarneDM

macrumors member
Jul 3, 2008
37
19
Korsør, Danmark, Europa
no opencore : the computer simply hangs and won't boot past the startup sound.

macOS on a cMP is only able to natively handle up to 16 GB RAM modules registered/un-registered.

The computer also hangs on the -screen if opencore has been mis-configured - eg you've specified 2x2 32 GB RAM but have inserted 2x3 32 GB RAM
 
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RAMtheSSD

macrumors regular
OK, I am thoroughly confused now! I was under the impression that the limit on the kind of ram was known and the problem solved: 32gb ram from the trashcan Mac Pro was good to go as long as one used only 5 slots. The limit of what could be addressed was left behind sometime ago with the move towards using Metal to draw the GUI. In that regard, 160 was made a limit by the 5 slot thing but the 5690 could handle nearly a terabyte of ram otherwise. In none of the things I have read has the motherboard been implicated as a limit of any sort. Natively, OS X can handle 128gb from the end of the "Big Awesome Cats" onward and that Mountain Lion and prior could only "see" (which is to say that the machine would boot but not be able to use all the installed ram) ~90gb?

(AFAIK) I can install Catalina just as I did Mojave with the sole exception of preventing the installer from checking the model identification. However, to go beyond today, I would have to install Open Core but --particularly in this thread-- not everyone is as enthused about the whole thing and particularly, what has to be done to get 256gb of ram working and how easy it would be to brick the machine one is working on?

The 32gb sticks have the same latency as the 16gb and 8gb sticks but they are notably faster than 1333mhz but will not go that fast because the 5690's top speed for ram is 1333? I was waiting to do two of the 32s because that would instantly double my ram but I can get 3 or 4 of the 16s for more of less the same price with the same speed; the issue is that both are registered ram and it wasn't that long ago that 8gb sticks were registered ram as well so that by waiting I could at least get 16s that were not registered?

Once the security updates stop, I plan on going to OpenBSD full-time and use a virtual machine for the times when only a Mac will do --since it is a Mac, there shouldn't be a problem, right? However, if I could use the 32gb sticks without Open Core there then I would migrate sooner to get the 256gb??

One last thing, in all of this thread, no one has said, as near as I can tell, anything about temperature regarding the more densely packaged ram under workload; has anyone had any issues with shutdowns due to heat?
 
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BjarneDM

macrumors member
Jul 3, 2008
37
19
Korsør, Danmark, Europa
When I got the first set of 4 x 32 GB sticks, I tested the motherboard issue by booting from an Ubuntu USB stick. Ubuntu was able to see the sticks without any issues.

Serve the Home has an excellent article on the differences and consequences : https://www.servethehome.com/unbuffered-registered-ecc-memory-difference-ecc-udimms-rdimms/

You don't "brick" you cMP by installing 32 GB sticks and trying to boot macOS - macOS seems to
  1. check the hardware
  2. determines it's a cMP
  3. assumes a max of 16 GB sticks
  4. refuses to boot if there's any 32 GB sticks present
I do think / assume that the 16 GB macOS limit might be due to the difference between unbuffered and registered RAM, where with 16 GB sticks both types works with the CPU , but for 32 GB and up only RDIMMs work, so  has played it safe.

IMG_4975.JPG IMG_4976.jpeg

I haven't had any issues with ♨️? as far as I can tell ??
Skærmbillede 2021-04-13 kl. 01.13.40.png
 
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RAMtheSSD

macrumors regular
Bjarne, thanks for the quick reply :) In a way, I am more twisted around though: I was under the impression that registered ram could not be mixed; that it would have to be all 16gb or all 32gb regardless of OS? From what you are saying, OpenBSD could be inferred to work with the 256gb but that could also be said to mean that FreeBSD would as well and isn't that basically Darwin? Now, I wasn't saying that the ram would brick the cMP, I was under the impression that it would boot with 5 sticks but not 6 of the 32. The bricking I was referring to is one that has been mentioned in this and other threads regarding OpenCore (you seem to be having ZERO problems) and that errors in configuring the ram would cause --I think it was even you that said that part-- real problems. I am glad that there is no issue with temperature (absolutely have to replace the plastic screws holding the Northbridge and its cooler together) although someone living in Scotland saying that would have less credibility than someone living in Dubai :)
 

BjarneDM

macrumors member
Jul 3, 2008
37
19
Korsør, Danmark, Europa
Correct - you can't mix unbuffered and registered RAM - that was one of my issues in my initial tests; for reference see the "Serve The Home" article.

I think it's safe to assume that you'll have no problems booting into 256 GB with any flavour of either Linux -or- BSD : the RAM limit seems to be an artificial limit set by  on the cMP specifically as demonstrated by the fact that
  • the newMP can address 1.5 TB RAM
  • the iMac Pro can address 512 GB RAM
  • if one uses OpenCore to bypass the macOS hardware check, one can address (at least) 256 GB
under Catalina; so it's not an explicit macOS limit in itself.

My issues with not being able to boot has been due only to misconfiguration of OpenCore.

Darwin is based upon FreeBSD - that's why  has to release the basic Darwin kernel as open source.
 

BjarneDM

macrumors member
Jul 3, 2008
37
19
Korsør, Danmark, Europa
So, no boot with the 32gb in OS X without OpenCore?
Correct - the cMP simply totally hangs at the boot/efi stage.
The same happens if you've misconfigured the RAM configuration for OpenCore.

Problem with OpenCore & Metal GPUs is if something goes seriously wrong,
you have to :
  • replace the RAM modules with some macOS likes (eg 16 GB to each CPU)
  • re-insert the original GPU (in order to get the boot-selection)
  • pull the RAIDZ1 HDs (partially) out (in order not to possibly damage the file system)
  • boot from an external FireWire HD (in order to bypass your misconfigured efi)
 
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