Hello,
At the time of our upgrade to 4.n, Odum chose a monolithic installation to take advantage of VMware's Fault Tolerance feature.
As upgrades have come and gone, we've split off TwoRavens/DataExplorer, and when we upgrade R we may move it to its own host for granularity/back-out.
From my absolutely unscientific observation I expect you'd achieve the greatest performance gains by breaking off the Postgres and Solr services onto their own VMs, which should shorten your disaster recovery window as well.
I hope this helps?
Donald