Guys trust me, it is not anyones PC or video Card that isn't good enough for this game. I just recently bought the game, Worked fine for about 2 hours, and then the game starts lagging so much that I have trouble rebooting my PC afterwards.
I have a 2.66GHZ Duo Core with a Geforce 8800 GTX and a Soundblaster X-Fi Fatality edition. I VERY MUCH doubt that my PC can't handle this game. I play crysis and a whole bunch of incredibly good looking games easily with out a spec of lag.
I have a G-15 keyboard with the little LCD screen which tells me my Ram and CPU usage. When playing Fable The lost chapters, I noticed that one of my cores stops working completely after about 1 hour of gameplay and the other Core is at 100%. Something is totally wrong with this game and its pissing me off. I was actually loving this game. I hope they fix this, cuz I want my money back.