Disk Churn

I have several hard discs connected (three lacie discs and one smaller one) and a couple of them churn constantly, using tons of cpu and slowing down the mac. Both discs I believe have large folders with samples in them, for use with Digital Performer and Machfive, music programs made by Mark of the Unicorn. I actually haven't used DP or Machfive in months, though they are both loaded onto my Mac.

I have activity monitor running and checked it. When the disks aren't connected, all is calm. When I connect them the cpu goes through the roof and the disks churn. The things that seem to be causing this are two programs? or system things? In activity monitor under Process Name: they are both called navx, and listed as User: Root.

Anybody know what that is by any chance? Or how to make it stop? Thanks!