I can inspect /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies with cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies.

This isn't limited to just Intel. I don't know if they are rounded or now.

Kernel version: 5.4.0-74

Relevant docs https://www.kernel.org/doc/Documentation/cpu-freq/user-guide.txt

I can inspect /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies with

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies

This isn't limited to just Intel. I don't know if they are rounded or not.

Kernel version: 5.4.0-74

Relevant docs https://www.kernel.org/doc/Documentation/cpu-freq/user-guide.txt