Hi buddies,
Apparently this is a problem with card driver. Various graphic cards present the same problem when newest drivers are installed. So, after stay tired of google it and bind it i tried myself a lot of tests and below i solved the problem for my NV GTX550TI:
installed the latest driver and in "nVidia Control Panel", go to 'Manage 3D Settings' and set 'Power Management Mode' to 'Prefer Maximum Performance'.
Only this configuration and passed few days without any problem. Games at max
I hope this help more people... So, let´s play
And please, if this work for you reply with an ok, alright!?