Hi, I upgraded my graphics card today from a GTX 260 (DX9) to a GTX 570 (DX11). Now within 2 hours of playing I've already had a couple of problems. I play in DX11, instead of DX9, obviously. Sometimes whenever a leader screen pops up the monitor just turns black, but the game sounds and everything continue. I have to ctrl+alt+del and manually close down the game. Another crash was just a complete crash. The game freezes (sound freezes too) and then restarts. Luckily I auto-save after every turn, so I didn't lose much progress. But it's still fairly frustrating. I bought a new card for better performance/graphics and I've already had quite a few crashes... Anyone know what could be wrong? Thanks.