MP 7,1 Mac Pro 7,1 RAM

[aagribeiro]

Hi,

I just bought a 16 core Mac Pro with 32Gb of RAM, and I'm now deciding how much RAM to buy from OWC.

I read Apple's support page regarding RAM configuration, and that the 7,1 supports 4,6,8,10 and 12 DIMM configs, even with different sizes. The documentation just mentions that if different DIMM sizes are used, the larger ones must be in the first slot. It doesn't mention other possible configurations (e.g. larger DIMMs on their own on a channel), so I'm in doubt whether the scenario I'm considering is supported.

Can I buy 2x64Gb (to keep my upgrade options as open as possible) and use the 4x8Gb that came with my machine? This config complies with the number of DIMMs restriction, but I'm not sure if there'll be a significant performance impact, or if this just won't work.

Has anyone tried such a config?

Thanks in advance,
Alex

 

[erroneous]

See page 19 of the Lenovo Xeon SP memory scaling document, the "Near-balanced memory configurations".

https://lenovopress.com/lp1089.pdf

I geekbenched a similar setup - the original 4x8Gbyte and and 2x32Gbyte - when I originally got my MP 7,1, along with some other configurations. Link below.

It'll work, has a measureable memory bandwidth performance impact, but unless your application is bandwidth limited, you probably won't notice a difference v hypothetical peak performance.

Mixing DIMM sizes in the MP7,1

I now have 6x32Gbyte 3rd party RDIMM and my original 4x8Gbyte RDIMM on my 16 core MacPro7,1. Below are Geekbench 5 (5.1.0) runs from some memory layouts I set up out of curiousity. RDIMMs installed Geekbench 5.1.0 test output Multi-Core "AES-XTS" result 12x32Gbyte...

forums.macrumors.com

 

[aagribeiro]

Thanks.

The Lenovo document is clear, although it doesn't justify the low performance you got for 4x8 (should be 67% if balanced). I'm getting 6 DIMMs of something.

Thanks again.

 

[Snow Tiger]

Thanks.

The Lenovo document is clear, although it doesn't justify the low performance you got for 4x8 (should be 67% if balanced). I'm getting 6 DIMMs of something.

Thanks again.

It's been said many times , many ways .

It's always best to use matching memory modules in a balanced configuration .

And , if you really want a rocket , go for channel optimization .

Your Mac has one processor with two memory controllers , each of which feels happy with three or six modules .

For the Mac Pro 7,1 that means six or twelve matching memory modules .

from Dell's Official Document on installing memory in Cascade Lake Xeon Systems (aka 2nd Gen Scalable ) .

https://downloads.dell.com/manuals/common/balancing_memory_xeon_2nd_gen.pdf

Don't worry about this being a recommendation for Dell Systems . Our Mac Pros use the same general family of processors and the memory controllers are in-silicon .

 

[ZoomEnhance]

Thanks.

The Lenovo document is clear, although it doesn't justify the low performance you got for 4x8 (should be 67% if balanced). I'm getting 6 DIMMs of something.

Thanks again.

Definitely get 6 DIMMs of something if you can, though 4x64GB DIMMs will also work--with theoretically less performance.

But yeah I tried 2x64GB RDIMM + 4x8GB RDIMM but was never able to get my 7,1 to boot in that config. Other folks, seemed to have also experienced this. In my case, it might have been because my NEMIX DIMMs are dual rank v. Apple's single rank DIMMs.

OWC now also sells 64GB RDMIMM for the 7,1, but I was never able to get a straight answer from them whether they would work in that specific combination.

https://www.reddit.com/r/macpro/comments/f09aw4

 

[Meads]

What about getting 6x32GB and add another 2x8GB to the standard config so you have a 6x32/6x8 setup. Is this going to mess up performance over only 6x32 and leaving the other slots empty?

 

[aagribeiro]

Definitely get 6 DIMMs of something if you can, though 4x64GB DIMMs will also work--with theoretically less performance.

But yeah I tried 2x64GB RDIMM + 4x8GB RDIMM but was never able to get my 7,1 to boot in that config. Other folks, seemed to have also experienced this. In my case, it might have been because my NEMIX DIMMs are dual rank v. Apple's single rank DIMMs.

OWC now also sells 64GB RDMIMM for the 7,1, but I was never able to get a straight answer from them whether they would work in that specific combination.

https://www.reddit.com/r/macpro/comments/f09aw4

Yeah, I'll do that. It would be nice to keep the 768GB upgrade option available by using just two 64GB, but realistically I doubt I'll ever need anything above 128GB.

 

[Snow Tiger]

Yeah, I'll do that. It would be nice to keep the 768GB upgrade option available by using just two 64GB, but realistically I doubt I'll ever need anything above 128GB.

"640K of memory should be enough for anybody ," said a badly informed geek a long , long time ago .

 

[aagribeiro]

"640K of memory should be enough for anybody ," said a badly informed geek a long , long time ago .

My first computer had 1024 bytes of RAM, so I know a thing or two about needing more RAM . The "ever need" part, would be in the context of this particular Mac Pro, which I plan to keep for 5 to 10 years.

 

[codehead1]

My first computer had 1024 bytes of RAM, so I know a thing or two about needing more RAM . The "ever need" part, would be in the context of this particular Mac Pro, which I plan to keep for 5 to 10 years.

Same, and it took eight chips (1K by 1-bit)—KIM-1 ?

 

[flowrider]

To the OP - The configuration you propose in your first post is not recommend. To get the most out of your new Mac run only six or twelve Dimms. If six, all should be matching. If twelve all twelve should be matching or six should be matching and the other six should match each other. Any other congifuration will suffer a speed penalty.

As far as your RAM supplier, I recommend Data Memory Systems (DMS). They are Mac specialists and their RAM carries a lifetime guarantee:

Mac Pro Memory - 2019 12-Core Xeon W 3.3GHz 7,1

DMS offers DDR4-2933 (PC4-23400) Memory for your 12-Core 3.3GHz 2019 Mac Pro 7,1. 100% Apple Compatible and backed by a Lifetime Warranty.

www.datamemorysystems.com

My first Mac, a Mac Plus, came with 1MB RAM, I upgraded it to the max - 4MB ?

Lou

 

[Snow Tiger]

Same, and it took eight chips (1K by 1-bit)—KIM-1 ?

Wow , you guys beat me ( and I thought I was a hard act to follow ! )

The first personal computer I worked with was an Apple II / Apple II plus with 48 KB memory and floppy drives . It was a magical time - 1979 .

It was located in the same computer room that had some mini computers running assembly , cobol or fortran .

I remember our wicked instructor forced us to write code on that mini and the best results I could get were this :

( diligently spent the better part of days trying to write a pathetically simple program . )

( proud moment , execute ! )

ERROR - LINE 100 .

ERROR - LINE 101 BECAUSE ERROR ON LINE 100 .

ERROR - LINE 102 BECAUSE ERROR ON LINE 100 .

ERROR - LINE 103 BECAUSE ERROR ON LINE 100 .

and so on for several printed pages from the wide carriage dox matrix , buzzing away like an angry wasp on steroids with a bull horn .

These were harder to hide from the rest of the class than simply frantically pressing the return key on the mini's keyboard and forcing the incriminating evidence off the screen .

It was deeply traumatic . And I realized then I'd never have a career as a software tech .

It was in this environment people discovered you couldn't pry me away from those Apples . I wasn't even revolted by BASIC .

I eventually recovered and became a hardware tech .

 

[AidenShaw]

"640K of memory should be enough for anybody ," said a badly informed geek a long , long time ago .

Proven to not be a quote from a geek with a net worth of over $100B, and who recently picked up a small beach cottage near San Diego for $66M (Seattle can be grey and depressing some of the time - you need to buy some sunshine).

 

[Snow Tiger]

Proven to not be a quote from a geek with a net worth of over $100B, and who recently picked up a small beach cottage near San Diego for $66M (Seattle can be grey and depressing some of the time - you need to buy some sunshine).

I didn't say which geek , Silly .

Besides , who wants to live in a home so big you can't dust it by yourself ?