What does "Prefetch views unpack data" in APDQC module do?
Really depends on your workload. In some cases having all of the views data prefetched is faster, in other cases it's slower. If you have 50+ views then it's best to leave it off, if you have just a couple views, turning it on is faster. 

Side note: I created the patch for creating this cache in views, now I wish it was prefixed by the view name so prefetch would be easier.