This feature lets you compare any two memory snapshots.
To locate memory leaks, consider using the object generations feature.
To compare snapshots:
File | Compare Snapshot with...(also available from the popup menu) and select the snapshot to compare with.
A tab with "Comparison" view will open. The "Comparison" view contains the memory views "Class tree" and "Class list" with 2 columns: Objects (+/-) and Size (+/-). These display the differences in object counts and sizes. Positive values mean that Snapshot 2 (the later memory state) has more objects and/or its objects have the bigger total size.
100% of size corresponds to the total size of all objects in the old snapshot. Likewise, 100% of count corresponds to the object count in the old snapshot.