Hi Homestea,
Did you manage to reach any conclusion regarding the problems you are/were experiencing ? I have noted today on my reasonably high spec 32-bit Windows 7 machine that after ANRB s/w has been running for a few hours, the screen (both the map and the info ) are updating very slowly -,i.e. every 5-6 seconds, as opposed to the 1 second update set in preferences. Also when attempting to select items, they did not select until several seconds passed. At the point I ran a couple of other programs which ran normally. A quick shutdown and restart of the ANRB s/w and it was updating and responsive as normal again. Sounds similar to what you were experiencing. I'll keep a note of how long before it stutters from hereon, and also note the program memory usage both before/after the slow down. If this turns out to be an inherent Windows 7 problem then I guess it will become more prominent as others switch to Windows 7. We'll see.