I share with you also my experience.
I also have noise of -90db- -92db.
From my knowledge of wireless signals, -90db or -92db is a very low noise, close to no noise at all, so, for me it is very good.
So, if you connect a bad shielded usb 3.0 pendrive or hard drive you should see the noise increase due to interference between usb3.0 signal and 2.4ghz wifi.
And, if you change the country to another who permit more mw you normally should see a more level of signal not noise
When I check it, for me it is important the SNR (signal noise ratio)
From my experience, when I get:
- 5 dB to 10 dB: is below the minimum level to establish a connection, due to the noise level being nearly indistinguishable from the desired signal (useful information).
- 10 dB to 15 dB: is the accepted minimum to establish an unreliable connection.
- 15 dB to 25 dB: is typically considered the minimally acceptable level to establish poor connectivity.
- 25 dB to 40 dB: is deemed to be good.
- 41 dB or higher: is considered to be excellent.
If you look at the picture only the first one on the list is a low signal, but ok for me because it is a NodeMCU outside of my house to get the outside temperature.
Regarding irqbalance I didn't see any benefit, but I don't have a fiber connection, I have only 100mb Internet connection and I reach 90 with openvpn.
Latest days I tell to the people of this thread that I prepare a build with kernel 6.1, if somebody would like to test here it is...
Thanks and sorry for annoying post