No, video cards are backward compatible and can easily run with earlier versions of DirectX. Your computer freezing can have a number of possible causes. Your CPU could be overheating, you may have a bad power supply, your computer may be infected with a virus, the games affected may have issues with the driver revision you are using, or the games themselves may have a bug in them. It would help to know the specs of your system, your CPU and GPU temperatures, and which games are having this problem.