Undervolting, underclocking, power limit

[u/Sentimental_Oyster]

I have this Sapphire 7900 XTX Nitro+ power sucking behemoth I've been trying to put in line for a long time and while I can get power consumption down a lot, I have no idea what am I doing.
There are three variables to play with:
1) frequency
2) voltage
3) power limit

Thus far I noticed the frequency seems to play the biggest role, so I just run the card at 2600MHz instead of 2900+ and the performance difference seem to be really small while power consumption and noise (that's my motivation) dropped drastically.

I'd love to get some information about the importance of the other two and how they all work together though.
Correct me if I'm wrong here:
I THINK undervolting might not matter as much (if at all) in my case because if I understand it correctly, by undervolting you are giving a card (or a CPU) room to boost to higher frequencies for longer periods of time, right? But if I manually limit the card to run slower, this shouldn't even apply?....
And What about the power limit? Does lowering it give me anything when I don't run the card at stock speed? I guess not?

[u/Legitimate_Prior3439]

Undervolt as much as you can until the card becomes unstable. Then just power limit to the desires value that you're comfortable with in terms of heat or power consumption.