[vxxed]

Hi all. My coworker has been running OpenFOAM on two different machines and has encountered pretty severe issues with configuration settings.

Both computers are running windows, with some distro of linux in a VM, and OpenFOAM running in that with 4 cores and 24gb RAM dedicated. Parallel computing settings are enabled in all of the below test cases.

The sim we're running used to go for 5~6 hours on the FX8350 until the second integer processor was disabled in the BIOS settings for each of the cores. After this change, the sims started running an order of magnitude faster.

What is confusing to me is that the 12800H is on paper, faster in every way. However, the simulations run for longer than the unfixed FX8350 by at least 4x the time. To me, this screams of configuration issues more than driver issues, but have you all ever encountered something similar? Any recommendations on what to change to get it to work correctly?

[Tobermory]

If you are serious about running OpenFOAM for the mid or long term then your best bet is to install Ubuntu (for free) - dual boot if you need to, and run under Linux. Seriously - you will get a significant performance boost, and will not be subject to arbitrary limits from the VM software. That was my experience, anyway, from 5 or so years back.

[Yann]

I agree with Tobermory and if you need to stick to window, I would recommend using WSL which is in my opinion an easier/lighter solution than a VM.
Regarding the performance issues, I would also tend to compare performance on native linux install to avoid the multiple layers of uncertainties regarding hardware + windows + VMs setups.

I'm sorry it doesn't really answer the question though.
I don't know these specific CPUs but just in case you missed it, there is a CPU benchmark on OpenFOAM here: https://openbenchmarking.org/test/pts/openfoam