> Perhaps related to the "0.786049 [Firmware Bug]: cpu 0, try to use APIC520 (LVT offset 2) for vector 0xf4, but the register is already in use for vector 0x0 on this cpu" messages at boot?
This message should be from MCE (machine check facility) initialization on AMD for error reporting; and should be benign, though we can improve this. I suspect the sound problem was caused by something else.