Hi phearthepenguin (and not the reaper?)
Good to hear it's working on the new machine!
My AMD system pulled something quite similar, but it was sudden onset after a week of running just peachy. Chased it around the mulberry bush in the Linux box for several hours before I re-booted the hub and router out of desperation. Now everything runs fine. Since then, at the first sign of trouble, I re-boot everything in the network chain between the server and the affected box. So far, it's cleaned up all problems instantly.