Just upgraded from a GTX560Ti to a GTX670. I've crashed running through cities twice now, with the "Unable to detect DirectX device" error that i only ever saw while trying to tab out of full screen. I play in windowed mode. Never crashed with this error using the 560Ti or my old 460.
I've had that problem only twice, and it was while playing after CTRL/ALT/DEL to get to task manager (seriously SE, another game where DirectX crashes your game? Fucking terrible)
I rebooted and haven't had it since.
Just crashed 4 times in Hamlet with the same DirectX error. Bloody hell. Trying beta drivers and then older drivers and if it still doesn't work i guess i'll have to go back to my 560Ti.
i been using SLI from day 1 and i see no difference in preformance, its always ran smooth with v-sync & tripple buffering.
its probably better on the older cards maybe it fixed bugs.