Problems with NVidia GTX 460 graphic cards

Hello,

I have moved my crystalspace application to new hardware. Now I have an intel i7 CPU and two NVidia gtx460 graphic cards with 756 MB. My application consists of 3 crystalspace applications with different points of view which are synchronized over TCP on the same machine. Every application has its own display. With my old hardware I hade 30-50 fps in every application. Now I get only 1-3 fps and I’m not sure what’s wrong. When I start only 2 views I get about 100 fps per view. But if I load the third one, the fps on every view falls to 1-3 fps.
When I plug in my old graphic cards (NVidia Geforce 9600GT with 512MB) the application works without any problems. Does anyone have an idea what I’m doing wrong? I have also tested other graphic cards like Asus ENGT430 and Asus EAH5570. With this cards I get 30-40 fps, but when I move trough my virtual world I get many jerkings in some positions in the world.

My configuration:
CS 1.4
Windows 7 32bit
Recent graphic card driver from nvidia homepage
compiled with visual studio 2008

Thanks

Jacek