Our team is using a 2 yr old mindstorm's brick and an education version brick purchased this year. Both have firmware 1.31 downloaded and both are running on AA batteries (refreshed at the same time.) We notice a difference in how programs are being executed- I don't think the problem in this case is related to motor differences. For example, one brick will execute a 90 deg turn and run a loop driving forward until the ultrasonic makes it stop. The other brick seems to be jumping the loop - by this I mean it seems that while executing the turn, the ultrasonic sensor is activated and triggering a stop before the robot has driven forward. Are there any other software differences I might have overlooked? Both were running the same program written in the education disc downloaded program. The other variance we've seen is within loops- One robot will stay straight with a continuous loop, whereas the other has significant drift. I am willing to attribute that to motor differences, but would love to hear any other thoughts. Thanks Tom Team 2280 - The Blockheads -- To UNSUBSCRIBE or CHANGE your settings, please visit https://listserv.jmu.edu/archives/vadcfll-l.html and select "Join or leave the list". -- VADCFLL administrative announcements are sent via VADCFLL-ADMIN-L. Visit https://listserv.jmu.edu/archives/vadcfll-admin-l.html to subscribe. -- To UNSUBSCRIBE or CHANGE your settings, please visit https://listserv.jmu.edu/archives/vadcfll-l.html and select "Join or leave the list". -- VADCFLL administrative announcements are sent via VADCFLL-ADMIN-L. Visit https://listserv.jmu.edu/archives/vadcfll-admin-l.html to subscribe.