okay i might have just figured it out....
i think my pc need a new CPU :)
i ran the intel diagnostics tool while listening to music and when this tool hit the CPUStressW and CPULoad test i could clearly hear the crackles starting.
EDIT: tested the same thing with furmark -> Same result:
when the CPU load is close to 100% i clearly hear the crackling start.
could this be the case ? i mean im tempted to buy a used i7 6700k and just try swapping it
