It was hard to find, but with some multiple monitors I was reading it in realtime. After loading a savegame it starts at about 950MB, steadily rising to 2,3GB at the crash. CPU load was constantly between 20-30%. The strange thing is that my total amount of RAM wasn’t used. Also my desktop background dissappeared, making me to suspect the GPU-memory. I was hovering above a medium sized town during the whole time without moving the POV. There is 1 train line and 1 bus line in this city. All other games/apps I ran this week had no problem, including the latest 3D Mark.
Here is BTW a screenshot of my normal task manager after the crash: http://i59.tinypic.com/fz6jbk.jpg