Since 1991 I run the same benchmark on a variety of machines.  It is a fortran scientific program to calculate the electronic structure of solids and molecules.  It spends most of the time in Fast Fourier Transforms and linear algebra (BLAS). There are two sets of data, the metane and cubane molecules, and for each the code is run twice, first without linking to any library, and afterwards I try linking to several libraries to find which are faster.

Bottom line: currently the Raspberry Pi 4 ($55) is about 3 times faster than one of the fastest supercomputers of 1991, the Cray C90 ($30000000).