Sharepont 2013 On premises - Publishing Navigation and Performance Issues

Hi Everyone,

I am trying to diagnose an issue with a Web Content Management site collection that has spikes of performance issues with heavy database consumption at random times.  When it occurs, the most frequent source of SPRequest objects in memory and slow query logging issues all involve the Publishing Navigation PortalSiteMapProvider.  The WCM site collection is pretty extensive as is the navigation. 

Question is whether this is a common source of heavy duty database consumption and if the performance issues can be solved simply by increasing the availability of SQL Server memory or tempDB size or increasing the object cache size.

Has anyone else encountered this before with a Publishing site collection with a large navigation structure?

Thanks!

Mary