after installing Cuda drivers ..Mac crashes

hello
after installing Cuda drivers 3.0 and after 3.1 my MAc Pro restart each 15 minutes by him self
or i have the message to restart my computer.
I lost already many work this way.
Where is the problem?
Maybe somebody have the idea?
Thank you very much for help

Mac Pro 3,2 Ghz Quad Intel Xeon
GeForce 8800 GT ( GPU )