You' ll need a fairly good PC to run it well. When the original Dawn of War came out it had high system requirements for the time. I don' t see this being any different.
Original Warhammer System Req:
3 Paintbrushes.
Every shade of brown and green known to mankind.
Overly-complex plastic sprues with mold lines you' ll never
fucking get off, no matter how good you are with an Xacto blade.
No social life,
whatsoever