Topic: OpenMP and AMD Ryzen CPU
I am trying to evaluate if the current AMD Ryzen offerings (Ryzen 9 or Threadripper) have limitations on their memory/NUMA architecture (not sure what the terms for this are) which will cause performance degradation when extending the number of OpenMP threads out to the maximum. So what do I mean by this?
For example, my current workstation CPU is an Intel I9 9900K processor, with 8 core and 16 threads. When I run my simulation with all 16 threads the performance is worse than if I use 8 threads. This suggests to me that there are memory access issues across the CPU chip that slow things down but not if I use only half the threads. The same happens for a Xeon E52680 chip that has 10 cores and 20 threads. I have to segregate the CPU by setting the affinity for the simulation to use half the available number of threads.
So does anyone here have experience with the AMD Ryzen chips? Specifically, I am interested in the Ryzen 9 3900X chip using OpenMP and threading limitations but discussion of the other AMD chips might help.
I am leery of AMD because I have been burned by them in the past where their 8 core CPU (I think the FX-8350) could not use OpenMP because of memory and core pipelines or something like that (LOL!).
Thanks in advance,