Comment 386 for bug 1690085

And if you want to test a single core benchmark pinned to a specific core to check what frequency can be reached, it is easy with following command:
taskset -c 10 openssl speed rsa2048

On my 1700X, cpupower monitor shows frequency up to 3880 for core 10 in the above benchmark.

If you want to stress two cores, you can either run two commands, or:
taskset -c 6,10 openssl speed -multi 2 rsa2048

Two cores go up to 3800 on my 1700X. Three and above go only to 3500. Two cores+multithread (taskset -c 6,7,10,11 for example) go up to 3650. This is the point where the new ryzen 2XXX are better, they can use higher turbo when using >2 cores. It seems they can do 4000 MHz up to 4 cores/8 threads with XFR2.