Just downloaded another chunk of Dapper updates on this laptop (70Mb this time) and can confirm that update-manager makes the system unresponsive for a long time while the updates are installed. I closed the laptop lid while it was updating, and when opening it I couldn't acitvate the screen again, ubuntu was completely unresponsive. Again the disk activity light was busy the whole time.
Just downloaded another chunk of Dapper updates on this laptop (70Mb this time) and can confirm that update-manager makes the system unresponsive for a long time while the updates are installed. I closed the laptop lid while it was updating, and when opening it I couldn't acitvate the screen again, ubuntu was completely unresponsive. Again the disk activity light was busy the whole time.