If checked, all calls to the AccuRev CLI on a particular node will be synchronized. That is to say, only one CLI operation can be going on at any time, across all jobs on a given node. The default is synchronized, which is the plugin's original behavior.

This sync was supposedly for problems with older versions of the AccuRev CLI. If you have a recent version of AccuRev (4.7+, possibly earlier), it should be ok to turn off synchronization. This can speed up operations significantly in some scenarios, such as with multiple jobs with large checkouts.