Hi Yogi - Could you please give more specifics? What monitors are you using? What kind of connections are you using (DVI, VGA, HDMI, DisplayPort, MiniDisplayPort)? Are you using an ACTIVE displayport adapter? What type is it?
Also - Did you uninstall the drivers and then install the latest drivers when you upgraded your card? Whenever changing cards even if its the same brand, I always uninstall the old drivers first, then install the new graphics card, then install the latest drivers. I do that to avoid potential driver problems but am not sure if that's applicable to your problem.