[mwmalkawi]

Dear All,

I appreciate your advice as I am in process of purchasing a workstation for openfoam to run transient analysis of say 20M cells so would you please specify me a specs I am thinking to buy *AMD Ryzen 9390x processor*of 16cores

Also does anyone know if there is a dual mother baord for AMD Ryzen 9390x

Or you recomend another processor type that could handle this size of mesh in the iteration and computational process

Thank you in advance for your kind help

[Simbelmynë]

You have your answer here.


Regarding the other question. If you talk about Ryzen 3900X, then No - there is no dual socket motherboard for that model.

[flotus1]

I would recommend something along those lines: https://geizhals.de/?cat=WL-1604742

You mentioned a budget of around 3000$ in private conversation.
You get a 16-core Epyc CPU with 64GB of RAM. That amount will be enough to run cases with 20M cells.
And I included a relatively large NVMe SSD as an intermediate storage medium for the operating system and the transient simulation results. Add one or more hard drives if you need more storage.
The beauty of this solution: if you ever feel like you need more performance, you can just drop in a second CPU with another 8 DIMMs, and effectively double the performance. Since motherboard prices for single-CPU are not much lower anyway, you would not save a lot of money by restricting your build to one CPU.

Not sure which Ryzen processor you had in mind originally, a 9390x does not exist. If you meant the Ryzen 9 3950x: the Epyc build is several times faster than that for OpenFOAM, even with a single CPU. And also the better choice compared to any Threadripper CPU.

[mwmalkawi]

Thank you do much for this valuable info you have made my life easy after your post I only have one more quirky please


For the mother board what do you think of the below model as it support AMD EYPC 7000 series so I dont know if 7002 series can be installed and fitted to it before purchasing it


Supermicro MBD-H11DSI-B Dual Amd Epyc 7000-Series Sp3 Soc Pcie

Also is there advantage in having PCI 4.0 compared to PCI 3.0

Thanks
Munaf

[flotus1]

About that motherboard...
The one I used is guaranteed to work with Epyc Rome (7xx2) CPUs.
If you buy an H11DSI that is not specifically sold as revision 2, there is a chance that you will get a revision 1.x board. These will not work with Epyc Rome CPUs, because the bios chip is too small to hold a Rome compatible bios.
Some sellers might ship a revision 2 board, despite not marking it as revision 2 explicitly. But you should definitely ask them before you purchase. If a seller has rev. 2 listed, they will definitely ship rev. 1 for other listings.
The whole situation is a mess, I know
There is a way to get a Rome compatible bios onto a revision 1.x board, but is rather involved compared to just buying rev. 2. https://forums.servethehome.com/inde...rome-es.28111/

PCIe 4.0 vs 3.0
If you want dual-socket, you don't have any option for PCIe 4.0 anyway. Supermicro H11DSi(-NT) is still the only board for system builders.
I do not consider PCIe 4.0 a must-have for a CFD workstation. If you want faster SSDs, you can still get them with PCIe 3.0. And PCIe bandwidth does not make a difference with the amount of GPU performance you need. If you are just concerned about compatibility: PCIe versions are mutually compatible, i.e. any PCIe 4.0 device will work on PCIe 3.0.

[mwmalkawi]

Thank you Flotus1 for the heads up regarding the motherboard rev02.

The issue with the link you sent me that it ships only to EU countries and it does not ship to UAE otherwise i would have ordered exactly the customization you specified. by any chance do you know any PC website that would ship to UAE.

Thanks again
Munaf

[flotus1]

I did not mean to suggest that you purchase any of the parts from the vendors in my list. This website is just a very convenient tool for me to find parts and compile a list. It is always better to purchase from a vendor in your part of the world. It makes handling returns or RMA much easier.
I can not give you any hints where to purchase these parts, especially the server-y stuff. I live in the EU, and only know hardware vendors there. I'm sorry, but I can not help you with that.

[Dr. Nubian]

What about:
1-Supermicro H12DSU-iN
2-Supermicro H12DST-B

[flotus1]

Those are proprietary server boards.
You will have a hard time finding them sold individually. You can not put them into any standard case. You can not power them with a regular ATX power supply. And I/O options are even worse than the H11DSI.

[Habib-CFD]

Originally Posted by Dr. Nubian

What about:
1-Supermicro H12DSU-iN
2-Supermicro H12DST-B

Some options for ATX board (PCIe Gen.4):
1-H12SSL-i (https://www.supermicro.com/en/produc...board/H12SSL-i)
2-TYAN Tomcat HX S8030 (https://www.tyan.com/Motherboards_S8030_S8030GM4NE-2T)

[Dr. Nubian]

According to supermicro, the H11DSi(-NT) still need to get revision 2 for EPYC 7002 series,
https://www.supermicro.com/en/produc...oard/H11DSi-NT

[flotus1]

Originally Posted by Dr. Nubian

According to supermicro, the H11DSi(-NT) still need to get revision 2 for EPYC 7002 series,
https://www.supermicro.com/en/produc...oard/H11DSi-NT

That's the working title of post #5 in this thread.

[JBeilke]

Originally Posted by Habib-CFD

Some options for ATX board (PCIe Gen.4):
1-H12SSL-i (https://www.supermicro.com/en/produc...board/H12SSL-i)
2-TYAN Tomcat HX S8030 (https://www.tyan.com/Motherboards_S8030_S8030GM4NE-2T)

These are single-processor boards. There are no PCI 4.0 dual processor boards available.

[mwmalkawi]

So shall I go with

1- dual socket CPU of PCIe 3gen of low speed RAM 26666MHz or

2- single socket CPU that support PCIe gen 4 with RAM 3200MHz

If you were in my place which option you choose for openfoam

[Dr. Nubian]

Originally Posted by mwmalkawi

So shall I go with

1- dual socket CPU of PCIe 3gen of low speed RAM 26666MHz or

2- single socket CPU that support PCIe gen 4 with RAM 3200MHz

If you were in my place which option you choose for openfoam

I think as flotus1 suggest if you thinking about upgrade or going to solve bigger mesh sizes or looking for faster solution in the future, then dual socket option give you chance to add another cpu with full range of RAM. Otherwise you go with single socket.



Adding to the fact that H11DSi-NT revision 2 support RAM 3200MHz

[JBeilke]

You can buy a dual-cpu machine with 3200MHz RAM.

[mwmalkawi]

Thank you all for feedback


appreciate help o below topics that are getting me confused here



1-) The motherboard states that it support memory speed up to 2666 Mhz, if i add 3200 MHz memory speed instead, would that be compatible, and motherboard utilize it or will it be downgraded to 2666Mhz due to motherboard limitation? in other words i will be installing RAM speed of 3200MHz but it will run at 2666MHz speed.





2-) as PCIe 4 has significantly better performance than PICe 3, what would be the performance impact for going with PCIe -3 especially if i decide to add another processors in the second socket where i will double the processing power, bandwidth and transfer required through PCI interface, as i ideally i want to utilize the 2 sockets with their capacity without any limitation coming from the motherboard such as PCIe3?


Thanks

[flotus1]

rev. 2 supports up to DDR4-3200, rev. 1 supports up to DDR4-2666. Same for Epyc Rome and Naples CPUs respectively.
Since basically all memory modules have profiles down to DDR4-2133 programmed, installing faster memory into a board/CPU combination that only supports lower speed, will result in the memory running at the lowest common denominator. There is no incompatibility from installing memory that is "too fast".

PCIe revision of the PCIe slots does not necessarily impact inter-CPU communication. I haven't seen a benchmark or any other definitive information about it, but my guess would be that you still get full inter-socket bandwidth.
And even if you didn't: there are other compromises in this budget build with way bigger performance impact. Mainly the choice of CPU and single-rank DIMMs, instead of dual-rank. At least in the context of OpenFOAM and its parallelization through MPI with domain decomposition. Which lends itself to minimize communication between cores.
And again, it's not like you really had a choice. I would be surprised if we see new dual-socket boards for system builders before AMD launches Epyc based on Zen3 architecture.

[mwmalkawi]

Thank you for this valuable info one last question

What would be the performance impact when using PCIe 3 vs 4 in terms of read / write processing bandwidth between the AMD epyc rome 7002 processor and the m2 nvme Ssd Samsung 970 PRO Series

Thanks

[flotus1]

None. Samsung 970 Pro is a PCIe 3.0 device.
Just for the record: I do not recommend a 970 Pro. It is a great option for a no-compromise build, where budget is of lesser concern. But for the scope of this workstation, a 970 Evo (Plus) is sufficient, at a much lower price.