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-   -   New workstation: Xeon, i9, Threadripper or Epyc (https://www.cfd-online.com/Forums/hardware/223664-new-workstation-xeon-i9-threadripper-epyc.html)

CRI_CFD January 21, 2020 10:58

New workstation: Xeon, i9, Threadripper or Epyc
 
1 Attachment(s)
Dear all,

I am planning to buy a new WS for simulation purposes. I will use mostly ANSYS, OpenFOAM and Lattice-Boltzmann related software (openLB, Palabos and maybe my own codes).

Based on a configuration I had in my former company, I asked for a new one in a well known shop here in Spain.

Here is what I had:

-Dual Intel Xeon E5 2600v3 series Socket 2011-3 Asus Z10PE-D16
-Doble CPU Intel Xeon E5-2620v4 2,1Ghz 20M Cache 8 Cores HT
-8x16GB Samsung DDR4 2133Mhz ECC REG configurada en QuadChannel
-SSD Toshiba 256GB Enterprise Edition
-SSD Toshiba 1TB Enterprise Edition
-Nvidia Quadro K1200 4GB DDR5 512 Cores CUDA
-Chasis E-ATX Aluminio con protección an-polvo.
-Fuente Silver 1000W PFC Acve


And please find attached the suggested configuration.

I am not sure if I am wasting performance with quad memory channel processors (insted of 8 channel processors). I would like to run simulation in parallel (and have the option to workn with GPU cores in the future).

I will run transient cases with about 4-8 million cells.

With these settings, do you consider the configuration suggested is good enough?
Should I move to another processors (slower but with higher count of memory channels)? Threadripper is quite expensive, and i not not sure if it will be the optimum choice for my purposes.
Is it better to save some money with the graphic card (what an amout of CUDA cores TR provides!)?


Please help, this is always a headache! I wish to have more knoweldge on hardware related to simulation....

flotus1 January 21, 2020 11:16

Based on the configuration in the image you attached, I would strongly recommend to avoid this seller. They are trying make you pay for getting rid of their old inventory. And on top of that, they don't know what they are doing.

2nd Gen Threadripper CPUs with 24 and 32 Cores have always been a horrible value for CFD-related workloads.Pairing it with only 2 sticks of RAM makes things even worse. Since the release of 3rd gen Threadripper CPUs, there is absolutely no reason to buy the previous gen with 24 or 32 cores.

If you want a Threadripper, get 3rd gen with 24 cores. But you will get way more performance from one or two Epyc CPUs with the same core count.
Trust me, I also write my own LBM codes and do benchmarks with them.
Also, I hardly think that a Quadro GPU will do anything for you. So you can probably save some money here if necessary. Case and power supply could also be cheaper.

CRI_CFD January 21, 2020 11:33

Thanks for the support, I was waiting for your reply :)

Could you please suggest a web seller more trustable than the one I posted?

Which Epyc proccessor you suggest to improve Threadripper performance for parallel CFD?

Should I need liquid cooling for the settings we are discussing?

Many thanks, your help is reallly appreciated.

flotus1 January 21, 2020 11:51

Unfortunately, I am not familiar with system vendors in Spain. Any chance you could assemble it yourself?
Some possible Epyc SKUs are 7402P for single-socket, or 7352 for dual-socket. Both have 24 cores, 8 memory channels and 128MB of L3 cache.
You don't need water cooling for these CPUs, a larger air cooler is enough. I would recommend Bequiet Dark Rock Pro TR4 or Noctua NH-U14S TR4-SP3. I am currently using the latter for the Epyc 7551 in my workstation.

CRI_CFD January 21, 2020 12:21

I am sure I would destroy components before being able to make them work :confused:

What about Germany? Do you have any seller you trust? Maybe they dispatch international orders...

The only webpage I found with several AMD Epyc is this one:

https://www.coolmod.com/component/se...earchword=epyc

Unfortunately, there 7402 is running out of my budget, 7352 is not available (7351 is half the core count of 7352), but 7551 is available and within a reasonable price. Do you think 7551 would work? 8*8 GB or 8*16 RAM is now the next choice...

I would be very grateful if anybody in the forum can recommend a good seller that ships to Spain (or even one in Spain with reasonable price and catalogue of AMD Epyc proccessors..)

flotus1 January 21, 2020 12:55

If I had to buy a complete workstation in Germany, I would probably order here: https://www.deltacomputer.com/workstation/amd-epyc.html

I wasn't talking about Epyc 7402, which is just a more expensive 7352. For single-socket, you probably want the Epyc 7402P, which is cheaper than the 7352. The P stands for single-socket in AMDs naming scheme.

I recently upgraded from 2x7301 to 2x7551. Mostly because they were cheap, and I already had the motherboard for it. At around 1200€ for a new retail CPU, and even cheaper offers on ebay, it can be a good option for system builders. But I doubt that any system vendor will give you these prices when configuring a workstation.
So in your situation, I would recommend you stick with 2nd gen Epyc (2 instead of 1 as the last digit of the name). At their initial retail prices, which you will have to pay to a system vendor, they offer much better performance/€. And if you only want one CPU, get one with a P suffix.

How much memory you want is entirely up to you, but with the model sizes you listed, 64GB total is probably enough. Just make sure to get 8 DIMMs per CPU to fill all memory channels.
There is an argument to be made for cheaper DDR4-2933 instead of DDR4-3200 for Epyc 2nd gen. Apparently, the infinity fabric on these CPUs stops at 1467MHz https://forums.servethehome.com/inde...1467mhz.27113/
So you loose some memory bandwidth, but get lower memory latency in return. If you need to save a few € on memory to make it work, I consider this an option.

CRI_CFD January 22, 2020 10:14

Many thanks for your reply. It seems the webpage you mentioned ships worldwide, so I will request a budget.

It is amazing how people help and interact within this forum. I wish you all the best.


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