You are experiencing the same issues as me then. I dont see any issues with my hardware and i think its just a poor programming in Epicor that is the bottle neck problem. I even went to the extreme and installed everything on the Fusion IO card on a dedicated machine and still performance was poor.
Let me know what the Epicor "performance tuning" comes up with, also who from Epicor wil do this performance tuning ? Ben Nixon ? If not could you let me know so i have some names to throw to my Epicor account manager since he has no clue to what is going on 
Thanks
/Joakim