Since I got the game, it doesn't seem to run as smooth as I liked. Then it gets to a point where if there's a ton of action on the screen, everything grinds to a snails pace. I'm sure the connection isn't the problem so I figure it's a part of my PC that needs upgrading (already got 2gb RAM). Which needs upgrading first? The Nvidea Geforce 7500 LE or Pentium D processor?