Strange CPU spike every five seconds with Fast Track Ultra

[foobuddha]

When any app engages the ASIO driver for my Fast Track Ultra, I see
a CPU spike every five seconds on one core out of four. It looks like this:

http://imgur.com/a/gHvRB

I don't have to be playing anything. As soon as I select the ASIO driver
for the unit, that pattern starts. It's attached to a process called "System Interrupts" and the description is "Deferred Procedure Calls and Interrupt Service Routines". When I select another ASIO driver (I have a Mia MIDI) the spikes go away. I don't have to even play anything. As soon as an app selects the Fast Track Ultra, the spikes start even when the transport is idle.

Thanks for any help!

Windows 7 64bit, Fast Track Ultra driver package 6.1.10.