Thanks for your replies!
It's tricky for me to change to the same OS for the three clusters, since they are all in production... I barely managed to get the users to do some benchmarking before they started using the newest cluster full time... I guess I can take one node from each cluster and install CentOS 7 and test again, but then I will need another program to test with. Any ideas? Also, I cannot use CentOS 6, since I guess the newest CPUs will not be recognized.
As for BIOS settings, I have followed the vendor's recommendations. When it comes to help from Supermicro, it has been very little so far. They told me to check out the tips given in a paper made by Intel and Ansys, but that did not give me much insight. It's more like a promotional paper; try searching for "Higher Performance Across a Wide Range of ANSYS Fluent Simulations with the Intel Xeon Scalable Gold 6148 Processor". The only comment that I found useful was "The improved vectorization, which is available as a runtime option in Fluent 18.1, was used in these benchmarks." I am pretty sure that version 19.2 of Fluent is aware of the Scalable processor features.
Anyway, since the core speed of 6146 and E5-2667 v4 is the same, I would think that it should at lest be equally fast. The faster memory (and we have populated all channels, as recommended) is supposed to be very important for Fluent, and this should make the 6146 cluster faster...
Do you know of any test program I can use to test single core performance, and also multicore performance, in a simple way from the command line? I can run this on one node on all clusters and compare. And if you know of any contact person or division in Supermicro that I can contact bout this matter?