How to Lower Minimum CPU Clock Frequency

Question

Recently I've been trying to reduce the cooling requirements of my desktop computer (since it gets exceedingly hot in summer), and have started looking into underclocking my CPU. Currently it idles at around 2.2 GHz, which is far higher then what I need it for on a daily basis. The trouble seems to be, according to cpufreq-info, that the 'hardware limit' of my CPU is fixed at 2.20 GHz to 4.85 GHz, and therefore none of the governors can go lower then 2.2 GHz.

I would like to reduce this 'hardware limit' down to 1 GHz, but can't find any way to do it, neither in the BIOS nor with any command line or GUI tools. How can I achieve that (ideally in such a way that I can still use the usual CPU governors should I need higher performance)?

I'm using the following:

• Ubuntu 20.04 LTS
• AMD Ryzen™ 7 5800X
• ROG Strix X570-E Gaming

Any advice or ideas would be greatly appreciated

A sample of cpufreq-info:

  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 15
  CPUs which need to have their frequency coordinated by software: 15
  maximum transition latency: 4294.55 ms.
  hardware limits: 2.20 GHz - 4.85 GHz
  available frequency steps: 3.80 GHz, 2.80 GHz, 2.20 GHz
  available cpufreq governors: conservative, ondemand, userspace, powersave, performance, schedutil
  current policy: frequency should be within 2.20 GHz and 3.80 GHz.
                  The governor "powersave" may decide which speed to use
                  within this range.
  current CPU frequency is 2.79 GHz.
  cpufreq stats: 3.80 GHz:8.11%, 2.80 GHz:50.42%, 2.20 GHz:41.46%  (2365)

EDIT: I'll also take an explanation for why this isn't possible and what my alternatives, if any, are as an answer.

Answer 1

Reasons (not an extensive list) why CPUs have minimum "safe" frequencies:

1. PLLs: Clock frequencies (cycling frequencies) are generated by PLLs, or phase locked loops, which take a reference clock, and perform modifications on the signal (in simple terms, multiplication or division) to reach the preferred frequency. This will limit the range of the clock, meaning that there will be a certain minimum frequency.
2. Other Components: The CPU is the main communication point between other machine components, more prevalent here being DRAM (dynamic random-access memory). DRAM needs to be constantly provided a clock, or there may be memory "lost" in missing clock cycles. Depending on the motherboard, CPU, DRAM, or other clocked components, this clock may or may not be provided by the CPU. If there are connected circuits making use of synchronous logic components (components that require a shared, constant clock cycle to run), that are receiving their clocks from the CPU, the CPU would need to provide at least that frequency.