-
-
October 28, 2021 at 4:28 am
FaizanYounas
SubscriberHi there. I want to know how to select the optimum no of cores for a simulation. Like, I have 64 cores right now and I have to run a mesh of 80,000 elements with time step size 1e-6. My simulation runs a lot faster if I give 32 processors to fluent instead of 64. Is there any way to figure out how many cores you should give fluent for optimum performance?
October 28, 2021 at 7:05 amaitor.amatriain
SubscriberThe number depends on many factors, but based on my experience it is between 10 000 and 100 000 cells per thread. In your particular case there are 80 000/60 = 1250 cells, which is a very low number.
October 28, 2021 at 8:37 amAmine Ben Hadj Ali
Ansys EmployeeFluent can operate at high efficiency even at very low cell count number. However this will also depend on the models you have and your hardware. I generally think that 100K per core is good average.
I can say 1 Million cells can be ran on 8 to 32 cores. Memory is also important so do not ignore that part!
October 28, 2021 at 10:44 amai0013
SubscriberTo add:
How are these 64 cores distributed? Sometimes depending on the architecture, e.g. having 2 sockets with 32 cores each can perform poorer compared to running with 1 socket. This is because the sockets need time to communicate with each other. Is that your case? Also depending on the grid partition some cores might finish their calculation before others, so they need to wait for them.
There other factors to consider in performance tests, I believe finding the optimum # cores is case-dependent.
October 29, 2021 at 3:00 amFaizanYounas
SubscriberThank you very much. My 64 cores are in 1 socket. I'm running now 160,000 mesh size on 40 threads and it's working okay. I'll try by reducing the cores and see it's effect on the simulation speed
October 29, 2021 at 5:53 amAmine Ben Hadj Ali
Ansys EmployeeÂÆ’æì
Viewing 5 reply threads- The topic ‘Optimum No of Cores For Fluent?’ is closed to new replies.
Ansys Innovation SpaceTrending discussionsTop Contributors-
3442
-
1057
-
1051
-
917
-
896
Top Rated Tags© 2025 Copyright ANSYS, Inc. All rights reserved.
Ansys does not support the usage of unauthorized Ansys software. Please visit www.ansys.com to obtain an official distribution.
-

Ansys Assistant

Welcome to Ansys Assistant!
An AI-based virtual assistant for active Ansys Academic Customers. Please login using your university issued email address.

Hey there, you are quite inquisitive! You have hit your hourly question limit. Please retry after '10' minutes. For questions, please reach out to ansyslearn@ansys.com.
RETRY