Hello. I have problems with using Gaussian 16 rev.A03 quantum chemical software on my AMD Epyc 7402P processor. I have «illegal instruction» error, when I try to execute calculation. I have tried fedora 31 (server, all updates), Ubuntu 20.04 (desktop), and RHEL 7.8 and 8.1 (server with gui). Both Gaussian 16 rev.A03 with AVX2 or SSE instructions do not work. The same program works perfectly on threadripper 1950x in fedora 31. The older versions of this program Gaussian 09 E.01 with AVX (1) instructions and Gaussian 09 D.01 with SSE are working normally on my AMD Epyc in RHEL 7.8. My motherboard is Supermicro MBD-H11SSl-I-B. Bios revision is 2.1 AGESA RomePi is 188.8.131.52 based on .14_RomeCrb_0ACMK013. I do not have source code of Gaussian 16 (only binaries) but I have found it is most likely compiled with Portand Group F77 16.5, gcc included in RHEL 7.3 and Atlas library (I don’t know it’s version). Please provide any help.