We have to make this option "true" to detect 100% dead streams. Dead streams are the streams for which the traffic was not at all received at the receiving port. And for these kind of streams Rx port name will be displayed as N/A.
If we are creating Dynamic result view(DRV) with filter condition set as Rx rate==0 to list the dead streams, then we should make sure that the option of "Enable Analyzer preload" is true (marked).
Note that, we will be able to see the option enabled under "All streamblocks" only when we have some streamblocks added.