Crazy idea. 32gb ram modules in a cMP. Anyone tried this?

[tsialex]

While MacPro5,1 CPU tray was designed for DIMMs with 1,5V VDD power rail, the standard voltage for DDR3, the PC3L DIMMs are backwards compatible and can run at 1,35V or 1,5V.

So, you can use PC3L DIMMs with a MacPro5,1. Usually PC3L DIMMs when running at 1.5V have power draw very similar of normal PC3 DIMMs, so , it's not a real advantage to install PC3L DIMMs - unless you find it cheaper/easier/the DIMMs have better heatsinks/etc.

 

[BjarneDM]

When I bought my cMP, it came with 6x8GB 2Rx4 PC3L 10600R
When I upgraded, I bought 6x16GB 2Rx4 PC3 12800R
I've had these inserted w/ 2x8GB PC3L + 6x16GB PC3 without any issues.

Generally, if the system can handle PC3 it can also handle PC3L, but systems designed for PC3L can't handle PC3
References :

What is DDR3L Memory | Dell US

www.dell.com

 

[jtgil]

Thank you very much for the prompt replies @tsialex and @BjarneDM! Thank you for clarifying!

And yes, my mistake, I realised too late that the PC3L DIMMs in a 1,5V rail wouldn't really use less power as they are of course, running at 1,5V...

 

[hirshnoc]

So just to clarify:

CustomMemory needs to be set to “true” using a plist editor, AND…

All memory needs to be IDed in Clover with Asset Tag, manufacturer, part number, size and speed all manually entered?

Is it one or the other, or both? Thanks.

 

[BjarneDM]

It's enough to
1️⃣ set "CustomMemory" to true
2️⃣ specify the correct RAM size and speed
3️⃣ only have entries in the slots you've filled (set size to 0 in the empty slots)
the other information isn't necessary - you can write whatever you want there

 

[hirshnoc]

It's enough to
1️⃣ set "CustomMemory" to true
2️⃣ specify the correct RAM size and speed
3️⃣ only have entries in the slots you've filled (set size to 0 in the empty slots)
the other information isn't necessary - you can write whatever you want there

The current iteration of Clover isn’t like what was posted years ago on this thread. Do you have an updated version that can be copied?

 

[BjarneDM]

Look, the basic process is as it's always has been :
1️⃣ follow the instructions from here : https://forums.macrumors.com/thread...n.2180095/page-53?post=28255048#post-28255048
2️⃣ use the relevant OpenCore Configurator version to modify the OC EFI config.plist

Ideally, you should have two ( 2️ ) HDs you can experiment with :
1️⃣ a stable good boot disk
2️⃣ an experimental boot disk
3️⃣ an external DriveDock
and believe me : you'll need this, as you'll invariably make some mistakes resulting in a non-boot situation.
You'll need to swap between 1️⃣ & 2️⃣ in a tray; and use the DriveDock to modify 2️⃣
You might be able to have both 1️⃣ & 2️⃣ in the trays & just pull 1️⃣when you want to boot form the OC EFI on 2️⃣ as the boot loader uses the 1st EFI it sees & ignores the rest; but that dependes on the boot loader seeing the HDs in the correct order, which isn't an assured situation.

As every MPc installation is different, publishing a config.plist serves no purpose. You'll have to experiment & find your own set of settings on your own.

As you can see in my signature, I'm still on OpenCore 0.7.4 + macOS 10.15.7 Catalina, as that's what's currently stable for me; I just haven't had the time to experiment with higher versions of either OC -or- macOS yet, as it's a PITA ? ? I've also got some old 2006 MacMini 10.6.8 Snow Leopard systems I'm using as servers ; and as AFP has been discontinued in macOS 11 Big Sur & macOS 12 Monterey, I'll have to get samba4 up and running on the 10.6.8 systems before I'm really able to update macOS to 11/12; and getting samba4 to play nicely is also a PITA ?

 

[358]

Hi Guys,

Before I go grey, can someone please tell me why 32GB DDR3 PC3L-10600L ECC DIMMS are not visible by my 5.1 (2012) with latest ROM and dual X5690 they just show as empty slots and if i try to boot with just the 4 x 32GB DIMMs i get a flashing power button. Are these sticks not compatible or faulty?

 

[h9826790]

Hi Guys,

Before I go grey, can someone please tell me why 32GB DDR3 PC3L-10600L ECC DIMMS are not visible by my 5.1 (2012) with latest ROM and dual X5690 they just show as empty slots and if i try to boot with just the 4 x 32GB DIMMs i get a flashing power button. Are these sticks not compatible or faulty?

Any picture of the DIMM's sticker?

 

[358]

Any picture of the DIMM's sticker?

 

[BjarneDM]

@358 have you tried booting w/ a Linux USB stick ?
Linux can see 32 GB sticks without any tricks; so if Linux can see them, it's your OC configuration that's toast

 

[358]

I struggle to understand how this is possible with the 32 gig dimms in the system it doesn’t even post there is no chime there’s nothing the power button just flashes as if I have bad memory so why would it be OC issue? hasn’t even gotten to the bios yet

 

[BjarneDM]

@358 Linux doesn't use OC ; errors in OC typically gives those errors

 

[KACTER]

It's a LRdimm , not the more common Rdimm one , and which Mac can't use it .
Mac can boot with 32GB PC3L-10600 'R' but not 32GB DDR3 PC3L-10600 'L' .

 

[BjarneDM]

as @KACTER wrote : that's server memory of the LRDIMM type ; it's electically incompatible w/ DIMM & RDIMM ; we've discussed this before in https://forums.macrumors.com/thread...a-cmp-anyone-tried-this.2046693/post-29823264

@358 If you've paid for it, then if possible return it for a refund -or- exchange to (R)DIMM (I do think you can only get 32GB as RDIMM)

& plase note, you CAN'T mix DIMM & RDIMM even though a cMP can use both.

@KACTER : ypu've got PC3 & PC3L ; the 'L' indicates "low voltage" ; PC3 is the form factor w/ 240 pin ; you can get PC3/PC3L for both DIMM, RDIMM & LRDIMM, so the PC3/PC3L doesn't in itself indicate which type of DIMM one has gotten hold of

 

[358]

as @KACTER wrote : that's server memory of the LRDIMM type ; it's electically incompatible w/ DIMM & RDIMM ; we've discussed this before in https://forums.macrumors.com/thread...a-cmp-anyone-tried-this.2046693/post-29823264

@358 If you've paid for it, then if possible return it for a refund -or- exchange to (R)DIMM (I do think you can only get 32GB as RDIMM)

& plase note, you CAN'T mix DIMM & RDIMM even though a cMP can use both.

@KACTER : ypu've got PC3 & PC3L ; the 'L' indicates "low voltage" ; PC3 is the form factor w/ 240 pin ; you can get PC3/PC3L for both DIMM, RDIMM & LRDIMM, so the PC3/PC3L doesn't in itself indicate which type of DIMM one has gotten hold of

thanks that makes more sense.

 

[hirshnoc]

What type of RAM if it was labeled “32GB 4Rx4 PC3L-10600R?" It has both an L and an R in it.

It is LRDIMM? Or RDIMM? Neither?

 

[tsialex]

What type of RAM if it was labeled “32GB 4Rx4 PC3L-10600R?" It has both an L and an R in it.

It is LRDIMM? Or RDIMM? Neither?

PC3L = 1,35V voltage / 10600R = 1333MHz Registered.

PC3L RAM are backward compatible with 1.5V motherboards, like MacPro4,1 and MacPro5,1 CPU trays.

When the memory is Load Reduced, and not compatible with MacPro4,1/MacPro5,1 Xeons, the LR letters are usually side by side on the label, like 10600LR or just 10600L.

 

[reinforchu]

Hi everyone, I arrived at this forum because I wanted to implement 256GB of RAM on a Mac Pro Mid 2012 (Mac Pro 5,1) and boot macOS. The result was a great success!
I want to keep the procedure, so I will describe it here.

Mac: Mac Pro 5,1 / Mid 2012
Memory module: Samsung M393B4G70BM0-YH9 / DDR3L-1333 ECC Registered, 32GB*8
CPU: Intel Xeon X5690 3.46GHz @ 2 Processors

Reproduction procedure:
1. Set up Clover Bootloader on a USB stick
2. Set the memory module in config.plist to 16GB * 16Slot (this bypasses the 32GB memory module boot limit)
3. Install the memory module on the daughter board
4. Hold down the Option key and select the Clover USB stick from the EFI boot loader (EFI Boot)
5. Select the target macOS (I booted from NVMe PCIe Intel 660p 2TB SSD)
6. If the progress bar progresses, the startup is complete.

Memory module

About This Mac(Japanese)

About memory(Japanese)

memtest(Rember) test passed. It is correctly recognized as 256GB of physical memory.

Thank you.

 

[hirshnoc]

Hi everyone, I arrived at this forum because I wanted to implement 256GB of RAM on a Mac Pro Mid 2012 (Mac Pro 5,1) and boot macOS. The result was a great success!
I want to keep the procedure, so I will describe it here.

Mac: Mac Pro 5,1 / Mid 2012
Memory module: Samsung M393B4G70BM0-YH9 / DDR3L-1333 ECC Registered, 32GB*8
CPU: Intel Xeon X5690 3.46GHz @ 2 Processors

Reproduction procedure:
1. Set up Clover Bootloader on a USB stick
2. Set the memory module in config.plist to 16GB * 16Slot (this bypasses the 32GB memory module boot limit)
3. Install the memory module on the daughter board
4. Hold down the Option key and select the Clover USB stick from the EFI boot loader (EFI Boot)
5. Select the target macOS (I booted from NVMe PCIe Intel 660p 2TB SSD)
6. If the progress bar progresses, the startup is complete.

Memory module
View attachment 2027428

About This Mac(Japanese)
View attachment 2027429

About memory(Japanese)
View attachment 2027430

memtest(Rember) test passed. It is correctly recognized as 256GB of physical memory.
View attachment 2027431

Thank you.

Wow; does it matter if you have OC or OCLP installed?

 

[h9826790]

Wow; does it matter if you have OC or OCLP installed?

You can use OC / OCLP to perform the memory spoofing.

In fact, so far, we believe OC is a better option than Clover, because we believe OC is 100% safe for the cMP BootROM, but we aren't that sure for Clover at this moment.

[For info, OC build for both Hackintosh and Mac, but Clover should be build for Hackintosh only]

 

[hirshnoc]

You can use OC / OCLP to perform the memory spoofing.

In fact, so far, we believe OC is a better option than Clover, because we believe OC is 100% safe for the cMP BootROM, but we aren't that sure for Clover at this moment.

[For info, OC build for both Hackintosh and Mac, but Clover should be build for Hackintosh only]

Interesting. Doesn’t the config.plist have to be re-done every time OC is updated? Otherwise you’ll get a bricked restart?

 

[h9826790]

Interesting. Doesn’t the config.plist have to be re-done every time OC is updated? Otherwise you’ll get a bricked restart?

Clover is the same, you should not use old config for new Clover.

If you install Clover for memory spoofing then won't update it anymore. OC allow you to do exactly the same thing.

 

[M.Switch]

Hey Macrumors fam... I just successfully installed 8 x 32GB DDR3 10600-R ECCthat I purchased from OWC labeled as 2013 Mac Pro Memory... the RAM doesn' t have sticker that indicate anything like nemix or other vendors... It booted in 1 minute... I did not have any delay as mentioned in Martin Lo's install guide. here is the picture... This was done on a test box.. but you can believe i'll be installing it on the main rig tonight...

 

[M.Switch]

I think I posted in the wrong place again.. but I just wanted to let you (the collective) that I purchased what was labeled by OWC as 2013 Mac Pro RAM... the specs are 32GB PC3-10600-R ECC x 8 sticks... I installed it and it came alive in 1 minute... I had already set the config file to true.

Memtest underway... will post later...