I never used it myself, but have seen several posts on the net that this firewall (can) cause BSOD's.....
I read theres 2 or 3 version of this firewall. 1 software & 1 hardware. The hardware based 1 supposed to be good. But not the software based.
It is known to cause some problems,.. I have installed and used this firewall on several occasions (mainly to check for any conflicts with AV`s etc), I personally have not seen BSOD, but have seen many reports of this. My main concern with the nVidia firewall as been the fact that on all my installs there have been inconsistencies of the applications and/or the packet filtering. (ie, on some installs all applications are allowed internet access without permission,.. other installs I have seen that blocked ports/IP`s are not blocked, and connections are allowed without rules. I think this firewall is/can be a little unpredictable, and if you decide to install/try, then I would suggest that you have a restore/backup of your HD before you do.