I was also thinking it might be possibly a hard drive (the platter type)
Also, what Bizman posted sounds familiar, from past article readings...
Your VC temperatures you posted for idle: 42c ...speeding up to 80c running AH3, seems a bit high to me...especially the idle temp.... 80c seems high to me as well...
You posted that you have your VC fan speed set to 24%:idle/low load , then 36%: high load
I personally recommend to adjust your current set limits, or turn off the automatic fan speed control, then go in and for example: set the idle or bottom temp/fan speed to around 40-50% and set the under load/higher temp/fan speed anywhere from say 65%, 70% or even 80% or higher...
Just a recommendation....your temperature readings seems high to me, both for idle and for under load....
I don't know anything about your computer build, but one needs good adequate airflow ...
Hope this helps
TC