It runs fine, just tested it out yesterday on the 2.0 machine. If you already have Civ IV I recommend sticking with that one thought. V has some improvements but I got bored of it quickly.
I like Civ5.... very fun if your into turn based strategy games.
You might not run things maxed out graphics wise on giant maps near end game when tons of stuff is going on, but your machine should have no problems playing the game decently... I've played it decently on lower end hardware than that.