TaskManager shows no excessive CPU activity...
Well, if it's not CPU constrained, then it's possibly an I/O subsystem problem. Can you check in Windows Performance manager what files are getting high levels of I/O. Here's an example, showing the high level of I/O activity that RB can generate through SQLite journalling.
![](http://farm4.static.flickr.com/3507/3941386824_a48d45d557_o.jpg)
So much depends on how Airnav are using SQLite in their programming, when they commit transactions, etc. Maybe an area for Airnav to look at for performance tuning in the future.