An IBM X24 Thinkpad. GENERIC_LAPTOP kernel with acpi enabled. -current. 
auich(4) reports

auich0: measured ac97 link rate at 74160 Hz, will use 74000 Hz

Whereas on an apm-enabled kernel

auich0: measured ac97 link rate at 47984 Hz, will use 48000 Hz

under boot. The problem is my sound then is awkward slow. Should I file 
a PR? Are there any configuration issues I am not aware of? Are there 
any information besides full config and dmesg I should provide?

The reason for the slow sound is clearly that auich(4) cannot run past 
48KHz, but ACPI oddly sets it to 74000, which of course ends up yielding 
problems. The playback rate is 44144/74000 of the nominal rate. Trying 
to force playback rate up via audioctl(1) is in vain.

Anybody with a solution to this problem?