Yeah, the requirements are surprisingly high, but the graphics are quite nice. I suspect the backdrop alone eats up a lot of resources. Maybe they should have an option to play on a board or simplified background for low-end machines!
On another note the Tau are to be released soon - I have access to the beta as an early adopter but haven't felt like dipping into a beta where everyone is playing Tau and I've been playing a lot of DoW2 for the past couple of weeks.