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Snow Tiger

macrumors 6502a
Dec 18, 2019
854
634
Just upgraded the stock 32GB ( 4 x 8GB ) memory configuration to an aftermarket 96GB ( 6 x 16GB ) in order to activate six channel memory and my processor upgraded 28 Core System performance went through the roof . I finally have a respectable GB5 multicore score . It's actually at the top of the class .

The upgrade modules are Crucial model MTA18ASF2G72PDZ-2G9 .

With the upgraded 96GB ( 6 x 16 GB ) memory :

Mac Pro 7,1 ( 2019 ) 28 Core with 6 x 16GB memory GB5 score geekbench.png

------------------------------------------------------------------------------------------------------------

With the factory 32GB ( 4 x 8 GB ) memory :

GB3 results W-3275M copy.png


There's over a 20 percent improvement in System performance now . Everything else being the same .
 

AidenShaw

macrumors P6
Feb 8, 2003
18,667
4,677
The Peninsula
Just upgraded the stock 32GB ( 4 x 8GB ) memory configuration to an aftermarket 96GB ( 6 x 16GB ) in order to activate six channel memory and my processor upgraded 28 Core System performance went through the roof . I finally have a respectable GB5 multicore score . It's actually at the top of the class .

The upgrade modules are Crucial model MTA18ASF2G72PDZ-2G9 .

With the upgraded 96GB ( 6 x 16 GB ) memory :


------------------------------------------------------------------------------------------------------------

With the factory 32GB ( 4 x 8 GB ) memory :



There's over a 20 percent improvement in System performance now . Everything else being the same .
Can you look at the individual tests, and see if the performance improvement was consistent across all of the individual tests, or if just a couple of individual tests got better?
 
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Snow Tiger

macrumors 6502a
Dec 18, 2019
854
634
Can you look at the individual tests, and see if the performance improvement was consistent across all of the individual tests, or if just a couple of individual tests got better?

Ouch , I see my mistake . I should have uploaded the results to my PL account , so that they could be publicly compared in detail . Normally , I don't worry about the individual tests .
[automerge]1580310930[/automerge]

Between your two different memory configurations , there is a huge performance gain with what I guess is the memory configuration of 12 identical modules in the multicore results for certain tests .

The performance gains are with these individual tests : AES-XTS , Navigation and Machine Learning .

AES-XTS handles cryptographic protection of data on storage devices .

I don't know what Navigation refers to . Anyone ?

Machine Learning are the operations a System will perform to solve specific tasks not explicitly instructed to solve .
 
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TTD

macrumors member
Dec 30, 2009
32
2
Hi all,

I ordered my MP with the base 4x8gb, I then installed 4 x 32gb, but whenever I've tried to add the original ram back in the machine as an additional 32gb, I've had the error light and the Mac won't turn on (following the suggested ram slots from Apple, with all the small speed and RDIMM etc).

I've resigned myself to the fact that there's no way to get that to work, so I'm now going to order another 2 x 32gb to achieve the 6 chancel boost a few of you have mentioned.

I'm just wondering if you were using the suggested Apple ram slot configuration, or a different order for the 6 x 32gb?

And if in the future I wanted to another another 2 x 32gb would that be possible without more errors, or do I need to jump up to 12 x 32gb?

Thanks!
 

Onelifenofear

macrumors 6502a
Feb 20, 2019
800
1,527
London
Hi all,

I ordered my MP with the base 4x8gb, I then installed 4 x 32gb, but whenever I've tried to add the original ram back in the machine as an additional 32gb, I've had the error light and the Mac won't turn on (following the suggested ram slots from Apple, with all the small speed and RDIMM etc).

I've resigned myself to the fact that there's no way to get that to work, so I'm now going to order another 2 x 32gb to achieve the 6 chancel boost a few of you have mentioned.

I'm just wondering if you were using the suggested Apple ram slot configuration, or a different order for the 6 x 32gb?

And if in the future I wanted to another another 2 x 32gb would that be possible without more errors, or do I need to jump up to 12 x 32gb?

Thanks!

Firstly - the 32s are definitely RDimms? Not LRDimms? As you cannot mix them.

The performance hit on 4 Channels and 4 different sizes may be significant.

If you use 32GB DIMMs with other capacities, such as 8GB or 16GB...
...Install the 32GB DIMMs in the first slot of each channel pair.

So install the higher RDIMM into the number 1 slot of each channel Pair.

Confusing as hell... but this is correct.

1 Empty
2 Empty
3 32
4 8
5 32
6 8
7 8
8 32
9 8
10 32
11 Empty
12 Empty


2019-mac-pro-memory-configuration-diagram-slot-channel-dimm.png
 

TTD

macrumors member
Dec 30, 2009
32
2
@Onelifenofear Thanks for the detailed reply, appreciate it.

So the 8GB and the 32GB were all definitely RDIMM and not (LRDIMM) - I even had a replacement set of 4 x 32GB sent to me form the supplier to be sure (although the labels always showed them as RDIMM).

I tried the order you suggested but the Mac wouldn't turn on.

I think Apple seem to have changed their guide for mixing capacity (or am I going crazy...?):

Screenshot 2020-01-29 at 17.34.47.png


It looks like you install a 32gb and an 8gb paired in each channel - unless I'm misunderstanding that?
 

Onelifenofear

macrumors 6502a
Feb 20, 2019
800
1,527
London
Crazy I guess? :)

Basically it's Biggest you have in 1, smaller in 2

32gb in A1, 8GB in A2.... and for 8 DIMMS you fill up A,B,D,E

That's what I've seen and it worked for me with 10 RDimms -
Same config as 8 with my 2 extra 32s in 1 (C1) and 12(F1)

I suppose they could have made it more confusing if they really, really tried... perhaps added in some Roman numerals or Emojii.... First 32GB Goes in the VII ? Slot and your 8GB goes in the MXM1 ?

Apple needs an interactive thing.

Enter the RAM you have For example...
2 x 8 GB
4 x 16 GB
2 X 32 GBa

and it's gives you an exact map for the best config.

Any one from the Mac Pro team Lurking? I won't even ask for a Royalty!
 

bwinter88

macrumors regular
Jul 20, 2012
152
1,913
So if I have 4 x 64GBs, adding two more sticks bringing the total to 6 would increase performance significantly? That's what I seem to be understanding from this thread...
 

Onelifenofear

macrumors 6502a
Feb 20, 2019
800
1,527
London
So if I have 4 x 64GBs, adding two more sticks bringing the total to 6 would increase performance significantly? That's what I seem to be understanding from this thread...

Yes Definitely...

4xDimms is actually only 66% Performance ( bit more in reality )

you have 6 channels of memory access and you are Currently using 4.
it's like 95% performance with 6 sticks and 100% with all 12 ( so long as they are all the same )

From page 18
(actually that whole section explained it all... balanced and near balanced etc)

As you can see it's very easy to screw it up!


Number of DIMMs populatedConfigurationNumber of Interleave SetsRelative PerformanceBalanced or Unbalanced
11:0:0,0:0:0118%Unbalanced
21:0:0,1:0:0135%Balanced
21:1:0,0:0:0135%Unbalanced
31:1:1,0:0:0151%Unbalanced
31:1:0,1:0:0218%Unbalanced
41:1:0,1:1:0166%Balanced
41:1:1,1:0:0235%Unbalanced
51:1:1,1:1:0218%Unbalanced
61:1:1,1:1:1195%Balanced
18 Balanced Memory Configurations with Second-Generation Intel Xeon Scalable Processors
Number of DIMMs populatedConfigurationNumber of Interleave SetsRelative PerformanceBalanced or Unbalanced
72:1:1,1:1:1218%Unbalanced
72:2:0,1:1:1318%Unbalanced
82:2:0,2:2:0169%Balanced
82:1:1,2:1:1235%Unbalanced
92:2:2,1:1:1251%Unbalanced
92:2:1,2:1:1318%Unbalanced
102:2:1,2:2:1269%Unbalanced
102:2:2,2:2:0218%Unbalanced
112:2:2,2:2:1318%Unbalanced
122:2:2,2:2:21100%Balanced



"Measurements show about a 3% loss in memory bandwidth when using a Near-Balanced memory configuration as compared to a Balanced memory configuration as long as there are an even number of total memory ranks on each memory channel"

So 6x32gb + 6x16gb ore similar would be about 97% performance.

32 go in all the Channel (A to F) number 1 Sockets
16 go in all the Number 2 sockets.

So damn confusing!
 
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daveedjackson

macrumors 6502
Aug 6, 2009
401
262
London
got my Mac earlier this week. Ordered a Ram upgrade, but sadly they sold out mid order, so I've got 2 x 32gb. I plan on removing entirely the 32 (4x8gb) chips which shipped with it. It seems like a no-brainer.
 

jerrygladh

macrumors member
Jan 30, 2020
32
15
Which slots :( making my brain hurt
8GB in 3,5,8,10. 32GB in 1 and 12.
Using just the 4x8 stock gave me 14064 GB5 Multicore Score
Adding the 2x32 slowed me down to 12805
Will be much better when I get all six 32GB, I hope :)
 
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Onelifenofear

macrumors 6502a
Feb 20, 2019
800
1,527
London
Which slots :( making my brain hurt

8GB in 3,5,8,10. 32GB in 1 and 12.
Using just the 4x8 stock gave me 14064 GB5 Multicore Score
Adding the 2x32 slowed me down to 12805
Will be much better when I get all six 32GB, I hope :)


Odd the Performance loss should only be about 3% with mixed sizes.... the way I understand it you put the higher ones in Channel A then B etc. So... the 32s go in 8 and 10. and 8s in 1,3,5,12
[automerge]1580578925[/automerge]
Which slots :( making my brain hurt

8GB in 3,5,8,10. 32GB in 1 and 12.
Using just the 4x8 stock gave me 14064 GB5 Multicore Score
Adding the 2x32 slowed me down to 12805
Will be much better when I get all six 32GB, I hope :)


Odd the Performance loss should only be about 3% with mixed sizes (near balanced) so long as it's a 4 or more DIMMS* 4 6 8 and 12 Dimms Basically.

The way I understand it you put the higher ones in Channel A then B etc. So... the 32s go in 8 and 10. and 8s in 1,3,5,12

I have two 32Gb RAM sticks from Crucial working just fine in my 7.1

*Apple does say that only 4 or more are supposed in pairs... 1 or 2 can be used in the same channel (A1+2) for example but only for diagnostics...the performance with 1 DIMM is 18%!! and 2 only a bit better at 35%
 
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flowrider

macrumors 604
Nov 23, 2012
7,323
3,003
^^^^WOW - So much more than 2666MHz from here:


Now for me - If I have the standard four 8GB dimms and want to add two16GB dimms. Where would they go?

Lou
 

Onelifenofear

macrumors 6502a
Feb 20, 2019
800
1,527
London
^^^^WOW - So much more than 2666MHz from here:


Now for me - If I have the standard four 8GB dimms and want to add two16GB dimms. Where would they go?

Lou

That ram is DDR4-2666MHz for the 8 core. All the rest 12-28 take 2933.

You can put either in and 8 but will be down clocked to the slower speed...same the other way round... I'd check with them exactly what they are selling anyway...but yeah macsales and OWC are pretty expensive.

The 16s go in 8 and 10. and 8s in 1,3,5,12 - you will get a slight performance hit on the mixed memory.
 

flowrider

macrumors 604
Nov 23, 2012
7,323
3,003
^^^^I have a post in the marketplace asking if anyone would be willing to sell me their 8GB DIMMs after they upgrade. I would luv to populate all twelve slots with 8GB Modules. That would be my first choice. And, I don't think I will be mixing capacities.

Lou
 
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