I am experiencing exactly the same problem as the OP- iaantmon.exe is causing cpu spikes that in turn cause a system slow down resulting in stuttering audio/video etc. I have positively traced the cpu spikes to iaantmon, and because I am using a RAID setup I am not able to disable the process.
Does anyone have any recommendations for a way forward from this? Is it possible to roll back the driver as I only updated it a few days ago?
Thanks for any help.