Thanks for the digging so far..appreciate the share.
I have not yet succeeded in discovering how to change the hashing clocks. It appears possible.
The VRM voltages should be easy to adjust over I2C. Though I do not recommend it, yet.
They are easy to check/set, but like you, I wouldn't recommend it.. It can be a great way to try to keep your temps in the 'magic zone' but you need to watch the VRM amp loads and temps very carefully.
The values are an offset from a 'full' voltage value, which is 0.950 volts. The higher the value, the less subtracted from 0.950 value, with FFFF being ZERO subtracted. Older codes (like 0.91) came with much higher volts, and the current code (0.98) sets 0xff67, which works out to about 0.797 volts.. But even that value appears to be a 'suggestion' since each core on a die will be some variance off THAT number.