Mathematica version 12.3.1 just recently came out, and one of the biggest things is the support for apple silicon, the M1...I completely uninstalled version 12.3 and just reinstalled 12.3.1 to do some testing...after benchmarking and not getting a better result than on rosetta 2, I checked in in activity monitor if it's reporting running on the new Apple silicon, to find the new version is not running natively on the M1 chip.
Is this the case for every/any one else? Is there something specific that needs to be done?
SetSystemOptions["ParallelOptions" -> "ParallelThreadNumber" -> 4];can help some of the linear algebra routines. Try changing the number and varying the number to see if things improve. $\endgroup$