Data Insight - backlogged files

We are running Data Insight 4.5, with multiple indexer/collectors doing file scans and Fpolicy across nearly 2 dozen netapps.

Is there a 'best method' to address the lag between an event occurring (such as a file being deleted from a filer) and when the event shows up in Data Insight?  We are running our indexers/preprocessors at 30min, but our file backlock for most things remains over an hour.   We are not hitting much utilization on our collectors (averaging 3% cpu utilization and 40% memory on 64bit 12gb ram 8-core server2008r2).    

On the performance section, the backlog size is generally 30-100 files,  10mb-20mb.