MP 7,1 2933 MHz Memory. Really?

majus

macrumors regular
Original poster
Mar 25, 2004
208
114
Oklahoma City, OK
From the Apple Support Document, this:
All memory included with your Mac Pro is 2933MHz. Mac Pro models with 8 core processors operate memory at 2666MHz.
...
• Install DIMMs in identical pairs for each channel.
...

From cpu-world.com's info on the W-3245 cpu, I find this:
Notes on Intel Xeon W-3245
  • Maximum operating frequency in Turbo Boost 2.0 mode is 4.4 GHz
  • Maximum DDR4 memory frequency is for 1 DIMM per channel configuration. When 2 DIMMs per channel are populated, the memory runs at 2666 MHz
  • The processor has the following security, data protection and/or software features: Intel vPro technology, Mode-based Execute Control, Run Sure technology, Speed Shift technology, Volume Management Device and Boot Guard.
Of special interest is bullet point #2, which raises some questions for me.

1. How noticeable is that 10% difference going to be for most of us?
2. Assuming the Note is correct, why didn't Apple mention it?
3. Has anyone actually tried using only 1 DIMM per channel?
 

AidenShaw

macrumors P6
Feb 8, 2003
18,625
4,628
The Peninsula
1. How noticeable is that 10% difference going to be for most of us?
Unnoticeable.

Memory bandwidth benchmarks which are specifically written to disable the caches will show some difference. I call these "bandwidth virus" programs - they don't reflect the real world

Real applications typically are written to optimize cache utilization, and for the most part show very little difference with different memory configurations. See https://forums.macrumors.com/thread...bservations-with-various-mem-configs.1704700/ for tests comparing an MP 6,1 with one to four DIMMs. (Spoiler - there was little difference on most apps between one and four DIMMs.)
 
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Snow Tiger

macrumors 6502a
Dec 18, 2019
854
567
From the Apple Support Document, this:
All memory included with your Mac Pro is 2933MHz. Mac Pro models with 8 core processors operate memory at 2666MHz.
...
• Install DIMMs in identical pairs for each channel.
...

From cpu-world.com's info on the W-3245 cpu, I find this:
Notes on Intel Xeon W-3245
  • Maximum operating frequency in Turbo Boost 2.0 mode is 4.4 GHz
  • Maximum DDR4 memory frequency is for 1 DIMM per channel configuration. When 2 DIMMs per channel are populated, the memory runs at 2666 MHz
  • The processor has the following security, data protection and/or software features: Intel vPro technology, Mode-based Execute Control, Run Sure technology, Speed Shift technology, Volume Management Device and Boot Guard.
Of special interest is bullet point #2, which raises some questions for me.



1. How noticeable is that 10% difference going to be for most of us?
2. Assuming the Note is correct, why didn't Apple mention it?
3. Has anyone actually tried using only 1 DIMM per channel?
Apple is correct .

Although I still think 6 or 12 identical memory modules provide the highest performance , compared to other configurations . I am debating what final memory kit I should install in my personal MP , because a fully decked out kit will cost five figures 😮 . So , I still hesitate .

Besides , thanks to Aiden ( Hi ! ) I finally found a solid working memory test program that really works with the MP7,1 . It is called MemTest86 and it boots and runs nicely on a stand alone USB thumb drive . I am also in the process of making a super fast dedicated NVMe M.2 PCIe USB-C 10 Gbps ( whew ! ) thumb drive so I can run this test efficiently with our MP7,1s .

In the old days , we used to use a version of that test called Memtest For Mac and it usually ran in a macOS session pretty nicely . It usually played well with other programs during system load tests . It no longer works as well as it did and so a replacement became necessary .

The memory in my 8 Core MP7,1 ran at 2666 MHz with the factory chip and as soon as I upgraded the System to a Gold 6212U the same ram ran at 2933 MHz .

The speed difference is marginal . Only if your workflow involves high billable hours or time sensitive operations would you absolutely need the fastest performing modules .
 

DearthnVader

macrumors 65816
Dec 17, 2015
1,133
5,729
Red Springs, NC
I remember adding memory chips to an Applied Engineering Memory Upgrade Card for a factory upgraded Apple IIe > IIGS . I ran that puppy in ProDOS ( not GUI ) mode and it was lightening fast . AppleWorks and Beagle Bros were the cat's meow .
The Apple II's were great, but I don’t think I ever upgraded the ram on the Apple II Plus I used from ‘79-‘85.

It’s just so amazing how far we have come.
 
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Snow Tiger

macrumors 6502a
Dec 18, 2019
854
567
The Apple II's were great, but I don’t think I ever upgraded the ram on the Apple II Plus I used from ‘79-‘85.

It’s just so amazing how far we have come.
I actually used that Apple II for eight entire years to run a small factory , before I was required to obtain a DOS PC for EDI in order to have electronic inventory management for the benefit of the chain retailers I sold to . A great return on investment . Macs and Apple IIs did not offer any EDI software . That was a warning sign all was not well in the computer industry , as the Apple II once had ( in the late 1970s and early 1980s ) the greatest number of apps available for any platform . And a souped up Apple II running PRODOS roundly outperformed all the early Macs running its GUI , of course . This lasted until the release of the 68030 Macintoshes ( Mac IIci class computers , especially the souped up ones ) . GS/OS dragged the Apple II to its knees , so that OS had to be avoided in a real world environment . But lots of fun days relaxing with Apple Panic 😁 .
 

defjam

macrumors 6502a
Sep 15, 2019
795
731
I actually used that Apple II for eight entire years to run a small factory , before I was required to obtain a DOS PC for EDI in order to have electronic inventory management for the benefit of the chain retailers I sold to . A great return on investment . Macs and Apple IIs did not offer any EDI software . That was a warning sign all was not well in the computer industry , as the Apple II once had ( in the late 1970s and early 1980s ) the greatest number of apps available for any platform . And a souped up Apple II running PRODOS roundly outperformed all the early Macs running its GUI , of course . This lasted until the release of the 68030 Macintoshes ( Mac IIci class computers , especially the souped up ones ) . GS/OS dragged the Apple II to its knees , so that OS had to be avoided in a real world environment . But lots of fun days relaxing with Apple Panic 😁 .
That was because Apple wanted it to. The 65816 processor in the IIgs was capable of running much faster than the 2.8MHz Apple stuck it with in the IIgs. The theory is Apple didn't want the IIgs to outperform the Macintosh as so gimped it with a slow clock.
 
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worldburger

macrumors member
Jan 27, 2008
44
5
The memory in my 8 Core MP7,1 ran at 2666 MHz with the factory chip and as soon as I upgraded the System to a Gold 6212U the same ram ran at 2933 MHz .
Gold 6212U? Could you give the context you went with that over the variants Apple sells? I had to google the product just to figure out it was a processor 😆
 

Snow Tiger

macrumors 6502a
Dec 18, 2019
854
567
Gold 6212U? Could you give the context you went with that over the variants Apple sells? I had to google the product just to figure out it was a processor 😆
It is a Cascade Lake Xeon processor Intel manufactured to help compete against the powerful , lower priced AMD equivalents in the single processor server space . It does not survive a NVRAM reset in a MP7,1 since this processor only generates 48 PCIe lanes and this Mac requires the installed processor to have 64 PCIe lanes . There is a check upon start up , normally . What this means in reality is the Mac Pro 7,1 ( 2019 ) must have an Intel W series Xeon to operate normally or the Mac will eventually go offline and require processor replacement - a time consuming and delicate operation .
 
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