NTA Implementation Best Practices

We are having multiple SolarWinds products installed on the same server (one web server & one DB server). We are currently having NPM, NCM, UDT, IPAM & NTA enabled on the same polling engine (same web server). NPM is licensed for 2000 interfaces (almost fully utilized), and NTA is having most of the load I presume, as we have multiple routers connected to 6 upstream providers and passing huge number of VoIP calls per day (total VoIP traffic reaches 2TB of traffic on a normal day), and we are also the upstream provider for a Cloud Services Provider as well.

We notice that NTA is slow (whether generating reports, displaying certain information regarding an IP source or destination, etc..), and we feel that NTA is making the whole environment slow as well.

Is there any best practice from your own experiences that we might implement, like another polling engine, or remote pollers for remote sites, or anything else as such?

Any ideas or suggestions are highly appreciated.