@Oldgamer

Greetings fellow elder statesman. For what it's worth, I also have a (Winfast) 6600GT and I have no problems with the campaign map on 1024x768.

I have DirectX 9.0c and my NVIDIA driver version is not the latest (6.14.10.6693).

I presume your new card is for M2TW, I am sorely tempted myself to upgrade - just to see how shiny a Total War game can get.

Cheers.