CPU frequency scaling doesn't work on Mac mini G4

[Koakuma]

Hi,

I've just noticed a strange behavior regarding frequency scaling on the
Mac mini G4. When I tried to set the CPU frequency using powerd, it
(and "sysctl dev.cpu.0.freq") reports that the frequency has been
changed, yet a test using "openssl speed" shows similar performance
between the two frequencies.

Here's the result of running "openssl speed -evp chacha20" with
"powerd -n maximum" (1416 MHz):

type		16 bytes	64 bytes	256 bytes	1024 bytes	8192 bytes	16384 bytes
chacha20	40326.69k	61947.78k	70339.29k	72921.32k	73479.72k	73307.48k

And with "powerd -n minimum" (708 MHz):

type		16 bytes	64 bytes	256 bytes	1024 bytes	8192 bytes	16384 bytes
chacha20	40314.57k	62121.26k	70303.44k	72740.17k	73468.76k	73520.78k

I expect that openssl would run slower when the CPU frequency is set
to minimum, but that's not the case here. Is it a bug or did I use
the wrong program to measure it?

The system is a freshly-installed 12.0-RELEASE on the 1.4 GHz model.