I also ran a couple syncs with log messages compiled out. The log compilation options selectively remove all of the code for generating messages for a given level at runtime, which is a large amount - even if the messages are not output to the console or log they are still generated. But this removed all of that to the lowest level of logging. I've tested this before with the same result, but given the reduced sync time I decided to try it again. There was no noticeable difference in performance across the sync. So I remain confident that the logging system is very efficient. :)