Bummer 😒
Oh well, thanks for your help! I guess I'll leave it this way until I can get a new soundcard 😜
Or perhaps I could contact SDL devs in case they know a solution. (unless the power saving switch you mentioned might do the trick)
Anyway, in case anyone needs to make this modification, I made a diff patch with all the modifications:

The only one you need is the one in dosbox.cpp.
I have been considering adding something like this to fool the cpu scheduling on linux, however messing with the cpu governer works as well. (On my machine using the cycles=max 105% is enough to fool it.)

just google for linux cpu governor and pick your distribution, you want to have the performance one 😉

* I changed the topic title to its nornal name.

Qbix wrote:

The only one you need is the one in dosbox.cpp.
I have been considering adding something like this to fool the cpu scheduling on linux, however messing with the cpu governer works as well. (On my machine using the cycles=max 105% is enough to fool it.)

I think you misunderstood, I don't want it to take up 100% of the CPU 😜

Qbix wrote:

just google for linux cpu governor and pick your distribution, you want to have the performance one 😉

This is for DosBox with busyWait or without?

Qbix wrote:

* I changed the topic title to its nornal name.

But you didn't move the thread in it's appropriate subforum 😜

for normal dosbox and I didn't move it, because of reasons 😉

Completely forgot about this thread. Setting the governor to performance didn't fix anything, I can still hear the noise through the headphones. I also asked on the SDL community forums for a solution, will post here if I get an answer.