NVIDIA has closed down their forums after they noticed supicious activities:

NVIDIA suspended operations of the NVIDIA Forums (forums.nvidia.com) last week.

We did this in response to suspicious activity and immediately began an investigation. We apologize that our continuing investigation is taking this long. Know that we are working around the clock to ensure that secure operations can be restored.

Our investigation has identified that unauthorized third parties gained access to some user information, including:

◦username
◦email address
◦hashed passwords with random salt value
◦public-facing "About Me" profile information
NVIDIA did not store any passwords in clear text. "About Me" optional profiles could include a user