Question Help with undervolting an i5-13600 on Asus mobo ?

[ohm-ish]

Hi
Got my new rig going:

CPU: i5-13600k (5.1ghz)
Motherboard: Asus Z790-I Gaming Wifi
RAM: G.Skill Ripjaws S5 DDR5 6400MHz 2x16GB (XMP enabled)
GFX: RTX 4070

I really want low noise (and heat)
So I'm looking into simple CPU undervolting etc.
And I don't mind losing a bit of performance, so I figured also lowering the multi a few steps is fine

I started with XTU, climbed the voltage offset and right now I'm at this:

That changed everything.
The computer is much much more cool and silent overall now, but plenty powerful for my use.
Cinebench gives a score of 21.150 (multi) and 1.750 (single) and maxes out at 80c temp
This seems good enough for me

But I prefer to use BIOS instead of XTU
So I reset XTU and uninstall it. and go into bios.

I set the CPU to Sync All Cores and set the ratio to 47
A bit confused about how to set the undervolt, but I figured it must be the CPU L2 voltage?
I keep it at adaptive, set it to offset - and I put in 0.050 (let's start with that and see)

Then I reboot, and test with cinebench.
Boom the temps go up to 94c quickly.
I stop it right away and reset default in bios again
Hmm now what?
Can someone help me how to achieve the XTU result, but with BIOS tweaking?
Thank you

 

[ohm-ish]

Ok I realized that I was undervolting the wrong thing in bios..
I should lower the VRM core voltage, not the L2

So now I have multiplier / core ratio set to 47 and VRM cpu voltage set to -0.130
Seems ok for now. Computer runs cool and silent

In my mind lowering the multiplier / core ratio set to 47 is a good thing for temps/noise, but not sure if it's needed at all, or how it's related to cpu undervolting?
Should I try go with even lower cpu voltage like 0.150? or until windows crashes and then back it up a bit?
Undervolt protection is enabled in bios
Feel free to comment or help 😉