Same title, very different problem:
I can start multiple instances - 2,3,4 no problem - but as soon as the second instance is up, Windows (7, 64bit version) is reducing the priority of both instances to lowest priority. As soon as I manage to close one (very slow in game or fast via task manager) the other instance recovers to normal priority. Needless to say this leaves me unable to play with multiple instances.
Anyone else has this problem or knows a workaround?