MP 7,1 Any problems with running multiple RAM sizes?

[mBlomkvist]

Hi everyone!

I'm getting a 7,1 mac pro this week and specifically held off on upgrading ram. So I've got the base 32GB (4x 8GB).

I'm wondering what I should avoid. Initially I was thinking about going OWC but it looks like I could save money if I went through newegg or amazon.

NEMIX RAM 32GB (1X32GB) DDR4 2933MHZ PC4-23400 2Rx4 1.2V 288-PIN ECC RDIMM Compatible with Supermicro MEM-DR432L-CL01-ER29 Registered Server Memory

NEMIX RAM 32GB (1X32GB) DDR4 2933MHZ PC4-23400 2Rx4 1.2V 288-PIN ECC RDIMM Compatible with Supermicro MEM-DR432L-CL01-ER29 Registered Server Memory

www.amazon.com

I'm really just looking to get 64-96GB range. Will I run into bottlenecking if I'm running 4x 8gb and 1-2x 32gb?

Thank you!

 

[MCal27]

You have to be very careful with Ram configurations in the 7.1.I’ve configured a few now for clients and the machines won’t even boot if the Ram is not a semi supported configuration (flashing red light on PSU and power light next to power button) The last one I did was specced to 192Gb and I had to start with the 32gb chips and then gradually fill in the gaps with the remaining 16 and 8gb chips till I had a supported configuration.

 

[mBlomkvist]

You have to be very careful with Ram configurations in the 7.1.I’ve configured a few now for clients and the machines won’t even boot if the Ram is not a semi supported configuration (flashing red light on PSU and power light next to power button) The last one I did was specced to 192Gb and I had to start with the 32gb chips and then gradually fill in the gaps with the remaining 16 and 8gb chips till I had a supported configuration.

Oh wow that's interesting. Yeah I just read the apple instructions. They mentioned something like that.

Since you seem pretty aware of RAM for these new computers... is $280 for 2 32GB Dimms a good price? In the reviews people are mentioning that at the end of last year these are less than $200. Is there still a way to get them at closer to that price?

NEMIX RAM 64GB (2X32GB) DDR4 2933MHZ PC4-23400 2Rx4 1.2V 288-PIN ECC RDIMM Registered Server Memory KIT

NEMIX RAM 64GB (2X32GB) DDR4 2933MHZ PC4-23400 2Rx4 1.2V 288-PIN ECC RDIMM Registered Server Memory KIT

www.amazon.com

Thank you!

 

[flowrider]

Mac Pro 7,1 RAM

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...

forums.macrumors.com

Don't buy two modules of anything unless it's two 8GB DIMMs to complement the four factory 8GB DIMMs.

Read the thread I have attached above.

The configuration by MCal27 above should be avoided, it's a hodgepodge.

Lou

 

[mBlomkvist]

Mac Pro 7,1 RAM

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...

forums.macrumors.com

Don't buy two modules of anything unless it's two 8GB DIMMs to complement the four factory 8GB DIMMs.

Read the thread I have attached above.

The configuration by MCal27 above should be avoided, it's a hodgepodge.

Lou

Okay so I should start over essentially? I'm assuming 4x 16 is better than 2x 32? I don't see myself going over 128 anytime soon.

 

[flowrider]

Please read the post I linked above. You should run six or twelve of the same size and type of Ram Modules. or six of one type and six of another. to get to close to 128GB - run six 8GB and six of 16GB = 144GB.

You could run eight DIMMS - four 8GB and four 16GB = 96GB - For a performance hit. Configure like this:



Lou

 

[mBlomkvist]

Please read the post I linked above. You should run six or twelve of the same size and type of Ram Modules. or six of one type and six of another. to get to close to 128GB - run six 8GB and six of 16GB = 144GB.

You could run eight DIMMS - four 8GB and four 16GB = 96GB - For a performance hit. Configure like this:

View attachment 922678

Lou

Okay to be fair I did read it. I just wasn’t planning on getting 6 right away. I guess 6x 16gb is probably what I’m thinking of doing. That way I’ve got room for expansion but stay at 96gb which I think is plenty. I could be wrong but I don’t think I’m going to see much of an improvement beyond that when working in premiere and ae.

thank you for the information. Really appreciate it.

 

[codehead1]

I looked at this last night a bit, due to to unresolved questions. I'll put out a few things I figured out, feel free to amend with more info.

RDIMM vs LRDIMM

LRDIMM: higher memory density, higher cost, slightly higher power and latency compared with RDIMM. So, RDIMM unless you need the big configuration or plan to expand into it.

Rank

Additional 64-bit ranks come with a plus and minus—more ranks, more latency but more efficiency. They come in 1, 2, or 4 ranks. Reading the technical material, 2 or 4 is a slight win over 1, but after that you lose to the increased latency. In one of these threads someone said 1 is fastest, but it's not what I found. However, I think the difference is small, I don't think this should be an overriding concern.

Channels

This is the biggest deal, by far. A set of four DIMMs is twice as efficient as two, and a set of six will be three times as efficient as two. The six channels come in pairs, so the formula repeats—but note that these things don't sum, non optimal configurations subtract from optimal efficiency. So, while I've seen (another thread) someone say 12 x 8GB is faster than 6 x 16GB, I'm almost certain this can't be true. For instance, a configuration of ten DIMM is less efificient than six (or twelve).

Because the minimum supported configuration is four DIMMs, it seems the worst case you can get into is in mixing DIMM sizes. I see a lot of people getting the minimum 4 x 8GB from Apple, then adding 2 x 32GB for 96GB. But it seems that will get you into very inefficient "single pair" access when you get past the first half of memory (though optimal on the first half). I'd have to dig further into the details to know for certain, but it seems it must be this way.

Another thing that seems likely to be true is that I suspect upgrading as 6 x 16GB then picking up another pair of 8GB to add to Apple's four should be OK—two sets of six at different sizes. Put the bigger DIMMs as the first slot of each channel pair.

Feel free to correct me on anything. I still have my base 32GB, but after researching this last night I'll go with 6 x 16GB. Unless I can justify a reason to go 6 x 32GB right off.

 

[Blair Paulsen]

IMO, mixing RAM sticks to save a little dough is not worth the potential issues. If you think 48 will be plenty for you in the near term, and you are planning to get AppleCare, just go 6x8 from Apple and keep your powder dry. You'd still have 6 empty slots to put matched sticks in later if your needs change.
I'm actually planning to bite the bullet and get 96GB (6x16) from Apple with 3 years of AppleCare. Not the cheapest option, but it's enough RAM to get by and keeps Apple from blaming 3rd party RAM if the rig has issues. (Yes, one could reconfigure back to original shipped content for repair.) I'm betting on three things:
1) 3 years of AppleCare will run out just about the time that I really start to need more than 96GB
2) RAM will be cheaper per GB in 3 years
3) Likely upgrade would be to 192GB (12x16 total) so I could add 6x16 into the 6 empty slots with no waste

I should add that I have dealt with some pretty vexing issues over the years with 4,1 and 5,1 cMPs using mismatched sticks, so I may be a little paranoid...

 

[flowrider]

^^^^Agree, but what's important to note - FOLLOW THE RULES!!!! I can't emphasize that enough when it comes to the installation of RAM. Over the years I have followed the rules and I have never had an issue with RAM - NEVER!

Lou

 

[Blair Paulsen]

Agree Flowrider, but tracking down the technical details of 3rd party RAM sticks to troubleshoot systems was a nightmare. It's hard to follow all the rules when you can't verify the specs on the sticks themselves.

 

[flowrider]

^^^^Certainly agree there. My RAM supplier is a Mac Specialist. I have used them since the 80s.

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

Lou

 

[DFP1989]

Okay to be fair I did read it. I just wasn’t planning on getting 6 right away. I guess 6x 16gb is probably what I’m thinking of doing. That way I’ve got room for expansion but stay at 96gb which I think is plenty. I could be wrong but I don’t think I’m going to see much of an improvement beyond that when working in premiere and ae.

thank you for the information. Really appreciate it.

I wanted more than my stock 32GB, but 48GB wasn’t quite enough, so I ordered the OWC 6x16GB kit. Will eBay my stock 32GB RAM to make the upgrade even cheaper!

 

[codehead1]

I'm actually planning to bite the bullet and get 96GB (6x16) from Apple with 3 years of AppleCare.

The 96GB configuration is actually not so bad, price-wise. Sure, it's a premium of 50% over OWC, for instance, and you don't have the 4x8 sticks if you figure on selling them, but still a blip in the total cost of the Mac and it shows up installed and no worries. (The next step to 192 GB is another story, and it gets worse after that.)

I've used DMS for most of my upgrades since the '80s, but never had to test their service. I went with Nemix this time, also lifetime warranty, 30 day refund, they seemed responsive, 96 GB $489.99 plus tax, free shipping option. Ordered via Amazon in early hours of Wednesday, and here it is Friday afternoon shipped from Florida to California. Took a couple of minutes to install, works fine.

 

[MCal27]

Mac Pro 7,1 RAM

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...

forums.macrumors.com

Don't buy two modules of anything unless it's two 8GB DIMMs to complement the four factory 8GB DIMMs.

Read the thread I have attached above.

The configuration by MCal27 above should be avoided, it's a hodgepodge.

Lou

Err it’s a supported configuration. Confirmed by Apple Support... please take back your ‘hodgepodge’ comment... Just became the chips are of different from sizes.. it runs well..

 

[eflx]

IMO technically you can run some unbalanced configurations, but if you're buying a setup just to save a couple hundred bucks ... "you're doing it wrong".

Always wherever possible, buy all of the exact same sticks of memory and use all available memory channels. Either 6, or 12 sticks of the same size, make, and model of high-quality name brand RAM. It's an expensive machine, why cheap out on a component like RAM? OWC stuff is garbage, toss it in the trash.

You'll see much better performance with these Xeon based workstations not mixing and matching - there are benchmarks all over the place to show the difference in memory performance with a quick Google search between both Windows PC and Mac Pro '19 performance with different memory setups.

 

[MCal27]

with respect you are misunderstanding how ram in the new Pro works... It’s a new machines so understandable, but the highest capacity chip needs to go in certain slots then smaller chips can fill out the remaining slots in a specific order without performance penality

 

[eflx]

I'm not misunderstanding at all. You can do it, but it does have a performance impact. This isn't a special "Mac Pro" feature, it's the same for all Xeon based systems including Lenovo workstations etc. where you can download a spec sheet on RAM configurations that give you a bit more technical detail.

 

[MCal27]

well ok then... your welcome to your reality. Apple’s Ram advisor App in the Pro 7.1 says different and I’ll follow that over internet advice. Have a nice day.

 

[KeesMacPro]

@MCal27 :
Back in 2009 the MP4,1 was shipped with a minimum of 3GB and the max of RAM was 32GB, according to the Technician Guide.
If you look at the specs of a common used cMP now, thats a different cookie.

The recommendations about how to upgrade the RAM are based on knowledge and experience, simply to avoid performance loss and possible issues in the future...

So if somebody would tell me Frankenstein is a perfectly normal human being , I disagree...