This feature lets you compare any two memory snapshots.
To compare snapshots:
The Comparison tab with memory views Classes and Classes and packages will open. The views have 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.