MP 7,1 Mac Pro 7,1 RAM support

[rylim]

Currently, my MP 7,1 has 96 GB of RAM (12x 8GB), and I plan to increase the RAM capacity to at least 256GB. Here's the option I have.

Option 1:
Get 2 x 128GB RDIMM RAM and exchange with 2x 8GB RAM --> 336GB

128GB RDIMM Samsung M393AAG40M3B-CYFC0

Option 2:
Take off all RDIMM RAM I have and exchange with 4x 128GB LRDIMM --> 512GB (LRDIMM requires 4 slot installed)

A-TECH 128GB Module DDR4 2933 PC4-23400 ECC LRDIMM 4Rx4 1.2V


I get that it is not an apple-to-apple comparison between options 1 and 2, but I'm looking for a future-proof investment in the RAM, and I favor option 1 because it is cost effective. However, I do have some concerns as follows:

1) Is it an issue to mix the 128GB RDIMM stick with the existing 8GB RDIMM stick?
2) In the long run, is RDIMM RAM better than LRDIMM in terms of performance?
3) LRDIMM has a Quad Rank (4Rx4), whereas RDIMM has a dual Rank (2SRx4). Should I opt for LRDIMM?

Ryan

 

[DrEGPU]

My 7,1 handles mixed RAM quite well. I had 8x 32GB sticks plus 4x 8GB sticks. As long as both sets are the same speed or neither are below what Xeons can handle (2933MHz?), it should work well.

As for RDIMM vs LRDIMM, I don’t have much knowledge or experience on that

 

[flowrider]

I would not mix - but that's me. Also I would only use a RAM configuration that utilizes either six or twelve slots with matched DIMMs.

Lou

 

[kvic]

You won't want to plan too far into the future because 7,1's (hackable) lifespan won't be as long as cMP. That's to say you plan to primarily run on MacOS, and sometimes Windows 10. If you're fine with Linux, then surely you'll get a hell long of years out of it.

It's imperative to make use of all six memory channel for best bandwidth & latency.

Also, pick LRDIMM modules if you plan to go >= 384GB. Or else RDIMM is fine. At least that's the way Apple practices their 'best practices'.

So perhaps in one shot go with 6x64GB LRDIMM. If you really have a need in future, double down by adding another set of 6x64GB to give 768GB.

 

[rylim]

You won't want to plan too far into the future because 7,1's (hackable) lifespan won't be as long as cMP. That's to say you plan to primarily run on MacOS, and sometimes Windows 10. If you're fine with Linux, then surely you'll get a hell long of years out of it.

It's imperative to make use of all six memory channel for best bandwidth & latency.

Also, pick LRDIMM modules if you plan to go >= 384GB. Or else RDIMM is fine. At least that's the way Apple practices their 'best practices'.

So perhaps in one shot go with 6x64GB LRDIMM. If you really have a need in future, double down by adding another set of 6x64GB to give 768GB.

My MP7,1 has been with me 2 years, so I think it is time to upgrade some of the parts which allow me to use it for another 5-6 years

Primarily, I will be running on macOS only and I notice that Apple nowadays only supports 6 years of macOS updates, which worries me. My MacBook Pro 2016 is no longer on the new Venture macOS-supported list.

Is it a specific reason to go for LRDIMM? RDIMM has a stick RAM up to 128GB nowadays, though.

I was thinking of mixing 10x 8GB + 2x 128GB, which fully all memory channels; Not sure if it will be a good idea.

 

[jscipione]

Can we put 3TB in yet or are we still limited to 1.5TB?

 

[freddiezzz]

This note from OWC might help:

NOTE: Mac Pro can use either RDIMM or LRDIMM, but they cannot be combined. Additionally, LRDIMM modules must all be of the same size.
Configurations of 5, 7, 9, 10, and 11 DIMMs are not supported. Other configurations of 1, 2, and 3 DIMMs are for diagnostic use only.

 

[rylim]

So far, I have been using 4x 128GB RDIMM stick, and there isn't any issue.

Unfortunately, MP 7,1 is limited to 1.5TB with 12x 128GB sticks