How do I determine all components controlling CPU frequency?

Two requests please:

1. Can someone tell me how I can determine all the components that are a) installed and b) actively controlling CPU frequency on an installation?
2. And separately, can someone tell me where the documentation for those components is?

[For context, the forum seems to be riddled with questions on the topic of "how do I set/control/limit the range of" cpu frequency, and many of them don't seem to get actual accepted answers. I have one such, so I will have to try to learn enough to work this out for myself. Unfortunately, the docs have so far mostly eluded me, and I have failed to find the "root" document, if such exists" that describes the overall concepts. So, I'm left with a system that seems to break the rules by clocking the CPU slower and slower (down to 240 MHz!) on a system that seems to be limited to 800 MHz - 2.4 GHz.]

EDIT follow up to Pilot6's comments/answer:

1. It's an Intel CPU (Core Duo)
2. The scaling driver is acpi (why would that be? what governs that decision--it's that way out of the box)
3. I tried changing scaling_min_freq, and the system overwrote it (with a value that doesn't match what the BIOS uses for "IntelSpeedStep")
4. it makes no difference whether speedstep is enabled in BIOS
5. it runs much slower than min_freq, which makes your final comment about hardware issue particularly interesting.
6. It slows down (per my other thread here: CPU clock speed slows way down Dell / Intel Core Duo (Lubuntu and others) ) when under long term load, but seemingly without getting too hot (~65C). It also takes forever to speed back up (but it does eventually).

TIA Toby