[vanhoivanbinh]

Hi all
I am setting up a spec for simulation computer
I use Ansys fluent (CFD) and Maxwell (transient simulation) and its coupling multiphysic simulation between the two modules in Workbench
I have HPC license with 16 cores total
I am currently looking up for "DELL Precision 5820 works station" with i9-10980XE CPU as it supports up to 256GB RAM and has 18 cores
For Maxwell simulation, I am sure it is enough as I am familiar with it
But for CFD, I am new
I do not know how much RAM I would need
My CFD model is estimated to have a mesh of 50 000 000 cells, and to deal with fluid flow thermal simulation.

How to estimate how much RAM and time for that CFD simulation model?

Thank you!

[flotus1]

Have a look at one of the pinned threads right in this forum: General recommendations for CFD hardware [WIP]
256GB of RAM should be enough for most CFD simulations on 50 million cells. Whether an I9-10980XE is a particularly good CPU for your application, is a different topic. I doubt it, and would recommend looking for proper workstation/server CPUs like AMD Epyc 7443P or Intel Xeon Gold 6312U.

[vanhoivanbinh]

Originally Posted by flotus1

Have a look at one of the pinned threads right in this forum: General recommendations for CFD hardware [WIP]
256GB of RAM should be enough for most CFD simulations on 50 million cells. Whether an I9-10980XE is a particularly good CPU for your application, is a different topic. I doubt it, and would recommend looking for proper workstation/server CPUs like AMD Epyc 7443P or Intel Xeon Gold 6312U.

Thank you so much
The i9-10980 is choosen as the Intel Cpu is better to work with ANSYS MAXWELL. For maxwell, it is the chip speed and core number rather than the RAM as one for CFD

[flotus1]

That's why I listed two alternatives, one Intel (with AVX512 support), one AMD.
A current-gen Xeon might still be a little slower than the old I9 when it comes to single-threaded workloads, but much better suited for for parallel CFD.

[vanhoivanbinh]

Originally Posted by flotus1

That's why I listed two alternatives, one Intel (with AVX512 support), one AMD.
A current-gen Xeon might still be a little slower than the old I9 when it comes to single-threaded workloads, but much better suited for for parallel CFD.

I got the available list of CPU from DELL today
It seems that the Intel Xeon Gold 6312U is not available for Workstation option. Only for Server option.

They list a bunch of other CPU and asking me to choose

Intel Xeon Gold 6254
Intel Xeon Platinum 8268
Intel Xeon Gold 6248R
Intel Xeon Gold 6242R

[flotus1]

Offtopic rant: that's just symptomatic for the current state of prebuilt PCs and workstations. Dell -one of the largest OEMs- still has not updated their lineup to the latest CPU generation. And proceeds to throw a bunch of wildly different top-shelf options at the customer.

From the list of CPUs you got, 6248R and 6242R are most suited to your use-case. The price could be the tie-breaker here.
Make sure the configuration comes with 6 DIMMs installed for the 6 memory channels of these CPUs.

[vanhoivanbinh]

Originally Posted by flotus1

Offtopic rant: that's just symptomatic for the current state of prebuilt PCs and workstations. Dell -one of the largest OEMs- still has not updated their lineup to the latest CPU generation. And proceeds to throw a bunch of wildly different top-shelf options at the customer.

From the list of CPUs you got, 6248R and 6242R are most suited to your use-case. The price could be the tie-breaker here.
Make sure the configuration comes with 6 DIMMs installed for the 6 memory channels of these CPUs.

Thank you so much
YEs, 6248R is a little bit higher than 6242R, but not much (400 USD)

If our ANSYS HPC license only support 16 cores (while the faster 6242R with 20C (3.1 GHz, 4.1 GHz turbo) and 6248R with 24C (3.0GHz and 4.0 GHz turbo)) which one you suggest for ANSYS CFD Fluent and ANSYS Maxwell 3D transient simulation?

[flotus1]

To be honest, I don't know how the coupling between Fluent and Maxwell works exactly.
Specifically, if there is a time window when both solvers do heavy lifting at the same time, using more than 16 threads total. In which case having more than 16 cores would be beneficial.
Don't worry too much about tiny differences between advertised clock speeds. With 20 cores active, both of these CPUs will probably turbo to the same frequency anyway.

[vanhoivanbinh]

Originally Posted by flotus1

To be honest, I don't know how the coupling between Fluent and Maxwell works exactly.
Specifically, if there is a time window when both solvers do heavy lifting at the same time, using more than 16 threads total. In which case having more than 16 cores would be beneficial.
Don't worry too much about tiny differences between advertised clock speeds. With 20 cores active, both of these CPUs will probably turbo to the same frequency anyway.

Thank you so much for your reply
Actually the coupling between Fluent and Maxwell will be very simple
1. Maxwell do the calculation then feed data to Fluent then it stops
2. Fluent do the calculation then feed the data back to Maxwell then it stops
The loop will be ended when it reaches a pre-set number.
There is no time that both Fluent and Maxwell running. Only single solver runs at a time

[flotus1]

The cheaper option it is then

[vanhoivanbinh]

Originally Posted by flotus1

The cheaper option it is then

Thank you so much!

[vanhoivanbinh]

Originally Posted by flotus1

The cheaper option it is then

For GPU, do you think one NVIDIA QUADRO RTX4000 8GB 3DP viturallink XX20T is enough?

[flotus1]

I wrote a section specifically about graphics cards. Yes, a Quadro RTX 4000 is more than enough.

[vanhoivanbinh]

Originally Posted by flotus1

I wrote a section specifically about graphics cards. Yes, a Quadro RTX 4000 is more than enough.

Thank you!!!!!!