Do this work for underclocking APU's too? (Ryzen 5 3000 Series / AMD Picasso)

Graphics:  Device-1: AMD Picasso driver: amdgpu v: kernel 
       Display: x11 server: X.Org 1.20.9 driver: amdgpu,ati unloaded: fbdev,modesetting,vesa 
       resolution: 1366x768~60Hz 
       OpenGL: renderer: AMD RAVEN (DRM 3.38.0 5.8.0-3-amd64 LLVM 10.0.0) v: 4.6 Mesa 20.1.8

I have a Ryzen 3500U (laptop APU)
Do you know if changing these values under /sys/class/drm/card0/device/ also work for controlling APU devices? Or is it mostly for dedicated GPU's separate from the CPU? Any known reports of people using these methods on APU's without side-effects?
I'm looking into ways of limiting the clocks of my APU, maybe setting to "low" preset will do.

I see this on /sys/class/drm/card0/device/pp_dpm_mclk:

0: 400Mhz 
1: 933Mhz *
2: 1067Mhz 
3: 1200Mhz

Does that asterisk on 1 means that 933 Mhz is currently selected? (I currently don't have any 3D apps open, just desktop and browser windows)
Can I manually set 0: 400 MHz to be used at all times? (regardless of load) How can I do that?
Changes take effect immediately or do I need to logout/login?
Being that this is an APU, any known side-effects with CPU clocks?

I'm doing this primarily to keep temps low and I will look further into how to limit fan speeds as well (if even possible, in my other laptop it wasn't possible) I want to avoid the fan spinning at max speed as much as possible, because that drastically reduces its lifespan. I had fans dying on me before, it's not easy to find replacements or to even replace them phisically. I would have to find into ways of limitting the "Max" fan spinning speed. If you happen to know, that would be great. On Windows, I would be able to achieve this manually changing DSDT table values.

sibradzic / amdgpu-clocks

Do this work for underclocking APU's too? (Ryzen 5 3000 Series / AMD Picasso) #21